STM32 Blue Pill HSPI1 and SN74HC595N 16x4 LCD Example

In previous post I use the HSPI1 communication interface of the STM32F103C8T6 to interface with the SN74HC595N serial-in-parallel out shift registers to control LEDs and 7-Segment display. In this programming example I use this chip to control the HD44780 compatible LCD controller. I use the TC1604A-01(R) LCM module from Tinsharp that I keep it many years now.

The SPI communication is one direction that the master micro-controller just send serial data including command and display data to the LCD module. Hence the LCD R/W pin must wired to GND. 

SN74HC595 chips in DIP package

 

The controlling mode is 4-bit data mode that need to send the 8-bit command/data twice via its high nibble and low nibble.

The MCU clock is 64MHz that is driven from its 8MHz HSI and PLL.

Clock Configuration

The operate in half duplex master mode with a baud rate of 16Mbits per second.

SPI and GPIO Setting

The NSS pin is ignored. So the enable pin must be set via software. I select PB4 as the SPI slave select pin. The Display Data RAM (DD RAM) of the TC1604A-01(R) is shown in the figure below.

I put the LCD driver with the main.c source code.

1. /* USER CODE BEGIN Header */
2. /**
3. ******************************************************************************
4. * @file : main.c
5. * @brief : Main program body
6. ******************************************************************************
7. * @attention
8. *
9. * <h2><center>&copy; Copyright (c) 2025 STMicroelectronics.
10. * All rights reserved.</center></h2>
11. *
12. * This software component is licensed by ST under BSD 3-Clause license,
13. * the "License"; You may not use this file except in compliance with the
14. * License. You may obtain a copy of the License at:
15. * opensource.org/licenses/BSD-3-Clause
16. *
17. ******************************************************************************
18. */
19. /* USER CODE END Header */
20. /* Includes ------------------------------------------------------------------*/
21. #include "main.h"
22. 
    
23. /* Private includes ----------------------------------------------------------*/
24. /* USER CODE BEGIN Includes */
25. 
    
26. /* USER CODE END Includes */
27. 
    
28. /* Private typedef -----------------------------------------------------------*/
29. /* USER CODE BEGIN PTD */
30. 
    
31. /* USER CODE END PTD */
32. 
    
33. /* Private define ------------------------------------------------------------*/
34. /* USER CODE BEGIN PD */
35. /* USER CODE END PD */
36. 
    
37. /* Private macro -------------------------------------------------------------*/
38. /* USER CODE BEGIN PM */
39. 
    
40. /* USER CODE END PM */
41. 
    
42. /* Private variables ---------------------------------------------------------*/
43. SPI_HandleTypeDef hspi1;
44. 
    
45. /* USER CODE BEGIN PV */
46. 
    
47. /* USER CODE END PV */
48. 
    
49. /* Private function prototypes -----------------------------------------------*/
50. void SystemClock_Config(void);
51. static void MX_GPIO_Init(void);
52. static void MX_SPI1_Init(void);
53. /* USER CODE BEGIN PFP */
54. 
    
55. /* USER CODE END PFP */
56. 
    
57. /* Private user code ---------------------------------------------------------*/
58. /* USER CODE BEGIN 0 */
59. 
    
60. /* USER CODE END 0 */
61. 
    
62. uint8_t DPORT;
63. 
    
64. void delay1(uint16_t dTime){
65. for(uint16_t i=0;i<dTime;i++);
66. }
67. 
    
68. void delay2(uint8_t dTime){
69. for(uint8_t i=0;i<dTime;i++) delay1(5000);
70. }
71. 
    
72. void en(void){
73. HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
74. delay1(1000);
75. HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET);
76. }
77. 
    
78. void lcdCmd(uint8_t cmd){
79. uint8_t temp=0x08;
80. DPORT=temp|(cmd&0xF0);
81. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
82. en();
83. delay1(10);
84. temp=0;
85. DPORT=temp|(cmd&0xF0);
86. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
87. en();
88. delay1(100);
89. 
    
90. temp=0x08;
91. DPORT=temp|(cmd<<4);
92. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
93. en();
94. delay1(10);
95. temp=0;
96. DPORT=temp|(cmd<<4);
97. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
98. en();
99. }
100. 
     
101. void lcdDat(uint8_t dat){
102. uint8_t temp=0x0A;
103. DPORT=temp|(dat&0xF0);
104. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
105. en();
106. delay1(10);
107. temp=0x02;
108. DPORT=temp|(dat&0xF0);
109. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
110. en();
111. delay1(100);
112. 
     
113. temp=0x0A;
114. DPORT=temp|(dat<<4);
115. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
116. en();
117. delay1(10);
118. temp=0x02;
119. DPORT=temp|(dat<<4);
120. HAL_SPI_Transmit(&hspi1,&DPORT,1,10);
121. en();
122. }
123. 
     
124. void lcdInit(void){
125. DPORT=0x00;
126. delay1(2000);
127. lcdCmd(0x33);
128. delay1(100);
129. lcdCmd(0x32);
130. delay1(100);
131. lcdCmd(0x28);
132. delay1(100);
133. lcdCmd(0x0F);
134. delay1(100);
135. lcdCmd(0x01);
136. delay1(2000);
137. lcdCmd(0x06);
138. delay1(100);
139. }
140. 
     
141. void lcdStr(uint8_t *str){
142. while(*str) lcdDat(*str++);
143. }
144. 
     
145. void lcdXY(uint8_t x,uint8_t y){
146. // 20x4 LCD
147. //uint8_t tbe[]={0x80,0xC0,0x94,0xD4};
148. // 16x4 LCD
149. uint8_t tbe[]={0x80,0xC0,0x90,0xD0};
150. lcdCmd(tbe[y-1]+x-1);
151. delay1(100);
152. }
153. 
     
154. void lcdClear(void){
155. lcdCmd(0x01);
156. delay1(12000);
157. }
158. 
     
159. /**
160. * @brief The application entry point.
161. * @retval int
162. */
163. int main(void)
164. {
165. /* USER CODE BEGIN 1 */
166. 
     
167. /* USER CODE END 1 */
168. 
     
169. /* MCU Configuration--------------------------------------------------------*/
170. 
     
171. /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
172. HAL_Init();
173. 
     
174. /* USER CODE BEGIN Init */
175. 
     
176. /* USER CODE END Init */
177. 
     
178. /* Configure the system clock */
179. SystemClock_Config();
180. 
     
181. /* USER CODE BEGIN SysInit */
182. 
     
183. /* USER CODE END SysInit */
184. 
     
185. /* Initialize all configured peripherals */
186. MX_GPIO_Init();
187. MX_SPI1_Init();
188. /* USER CODE BEGIN 2 */
189. HAL_Delay(100);
190. lcdInit();
191. lcdClear();
192. lcdCmd(0x0C);
193. lcdXY(3,1);
194. lcdStr("Hello World!");
195. 
     
196. lcdXY(3,2);
197. lcdStr("STM32F103C8T6 ");
198. 
     
199. lcdXY(1,3);
200. lcdStr("HSPI1 SN74HC595N");
201. 
     
202. lcdXY(1,4);
203. lcdStr("TC1604A-01R LCD");
204. 
     
205. HAL_Delay(5000);
206. lcdClear();
207. 
     
208. lcdXY(1,1);
209. lcdStr("STM32CubeIDE");
210. 
     
211. lcdXY(1,2);
212. lcdStr("version 1.6.0");
213. 
     
214. lcdXY(1,3);
215. lcdStr("HAL Library...");
216. 
     
217. lcdXY(1,4);
218. lcdStr("16/11/2025");
219. 
     
220. /* USER CODE END 2 */
221. 
     
222. /* Infinite loop */
223. /* USER CODE BEGIN WHILE */
224. while (1)
225. {
226. /* USER CODE END WHILE */
227. 
     
228. /* USER CODE BEGIN 3 */
229. }
230. /* USER CODE END 3 */
231. }
232. 
     
233. /**
234. * @brief System Clock Configuration
235. * @retval None
236. */
237. void SystemClock_Config(void)
238. {
239. RCC_OscInitTypeDef RCC_OscInitStruct = {0};
240. RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
241. 
     
242. /** Initializes the RCC Oscillators according to the specified parameters
243. * in the RCC_OscInitTypeDef structure.
244. */
245. RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
246. RCC_OscInitStruct.HSIState = RCC_HSI_ON;
247. RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
248. RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
249. RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2;
250. RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;
251. if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
252. {
253. Error_Handler();
254. }
255. /** Initializes the CPU, AHB and APB buses clocks
256. */
257. RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
258. |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
259. RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
260. RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
261. RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
262. RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
263. 
     
264. if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
265. {
266. Error_Handler();
267. }
268. }
269. 
     
270. /**
271. * @brief SPI1 Initialization Function
272. * @param None
273. * @retval None
274. */
275. static void MX_SPI1_Init(void)
276. {
277. 
     
278. /* USER CODE BEGIN SPI1_Init 0 */
279. 
     
280. /* USER CODE END SPI1_Init 0 */
281. 
     
282. /* USER CODE BEGIN SPI1_Init 1 */
283. 
     
284. /* USER CODE END SPI1_Init 1 */
285. /* SPI1 parameter configuration*/
286. hspi1.Instance = SPI1;
287. hspi1.Init.Mode = SPI_MODE_MASTER;
288. hspi1.Init.Direction = SPI_DIRECTION_1LINE;
289. hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
290. hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
291. hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
292. hspi1.Init.NSS = SPI_NSS_SOFT;
293. hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;
294. hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
295. hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
296. hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
297. hspi1.Init.CRCPolynomial = 10;
298. if (HAL_SPI_Init(&hspi1) != HAL_OK)
299. {
300. Error_Handler();
301. }
302. /* USER CODE BEGIN SPI1_Init 2 */
303. 
     
304. /* USER CODE END SPI1_Init 2 */
305. 
     
306. }
307. 
     
308. /**
309. * @brief GPIO Initialization Function
310. * @param None
311. * @retval None
312. */
313. static void MX_GPIO_Init(void)
314. {
315. GPIO_InitTypeDef GPIO_InitStruct = {0};
316. 
     
317. /* GPIO Ports Clock Enable */
318. __HAL_RCC_GPIOA_CLK_ENABLE();
319. 
     
320. /*Configure GPIO pin Output Level */
321. HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
322. 
     
323. /*Configure GPIO pin : PA4 */
324. GPIO_InitStruct.Pin = GPIO_PIN_4;
325. GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
326. GPIO_InitStruct.Pull = GPIO_NOPULL;
327. GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
328. HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
329. 
     
330. }
331. 
     
332. /* USER CODE BEGIN 4 */
333. 
     
334. /* USER CODE END 4 */
335. 
     
336. /**
337. * @brief This function is executed in case of error occurrence.
338. * @retval None
339. */
340. void Error_Handler(void)
341. {
342. /* USER CODE BEGIN Error_Handler_Debug */
343. /* User can add his own implementation to report the HAL error return state */
344. __disable_irq();
345. while (1)
346. {
347. }
348. /* USER CODE END Error_Handler_Debug */
349. }
350. 
     
351. #ifdef USE_FULL_ASSERT
352. /**
353. * @brief Reports the name of the source file and the source line number
354. * where the assert_param error has occurred.
355. * @param file: pointer to the source file name
356. * @param line: assert_param error line source number
357. * @retval None
358. */
359. void assert_failed(uint8_t *file, uint32_t line)
360. {
361. /* USER CODE BEGIN 6 */
362. /* User can add his own implementation to report the file name and line number,
363. ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
364. /* USER CODE END 6 */
365. }
366. #endif /* USE_FULL_ASSERT */
367. 
     
368. /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

I made my own DIY SN74HC595N LCD driver controlling a TC1604A-01(R) LCM module.

It can be used with some Arduino libraries. It is very easy to use as it needs only five pins.

Simulation #1

Simulation #2

I use Proteus VSM to simulate this example.

In real hardware this LCD module work at +5VDC only while the STM32 Blue pill input output logic voltage is +3.3VDC. However some newer LCD module with the HD44780 compatible LCD controller able to operate at +3.3VDC.

 

Running Program #2

Running Program #1

Click here to download this example. 

 

STM32 Blue Pill HSPI1 and SN74HC595N 7-Segment Display Example

In previous post, I use the SN74HC595N and the HSPI1 of the STM32F103C8T6 to control the output LEDs. This SPI chip could interface with any parallel input devices, 7-Segment, parallel port LCD, elector-mechanical relays etc.

For a simple example here I use a single common anode 7-segment display to show received SPI data.

 

I made my own SN74HC595N 7-Segment board for testing.

The SN74HC595N 7-Segment Board

 

The display I took from a scrapped HP Print-Scan-Copy device. The display type is common anode.

In this example the STM32F103C8T6 run at 64MHz that is driven from its 8MHz HSI oscillator and its Phase Lock Loop.

Clock Configuration

I use the HSPI1 module Master Half Duplex Mode operates at 16MHz. 

SPI and GPIO Setting

 

I use Proteus VSM to draw and simulate this programming example. The program will send the Hexadecimal from 0 to F before it reset.

Proteus Simulation Program

 

The source code I wrote is just a few lines.

1. /* USER CODE BEGIN Header */
2. /**
3. ******************************************************************************
4. * @file : main.c
5. * @brief : Main program body
6. ******************************************************************************
7. * @attention
8. *
9. * <h2><center>&copy; Copyright (c) 2025 STMicroelectronics.
10. * All rights reserved.</center></h2>
11. *
12. * This software component is licensed by ST under BSD 3-Clause license,
13. * the "License"; You may not use this file except in compliance with the
14. * License. You may obtain a copy of the License at:
15. * opensource.org/licenses/BSD-3-Clause
16. *
17. ******************************************************************************
18. */
19. /* USER CODE END Header */
20. /* Includes ------------------------------------------------------------------*/
21. #include "main.h"
22. 
    
23. /* Private includes ----------------------------------------------------------*/
24. /* USER CODE BEGIN Includes */
25. 
    
26. /* USER CODE END Includes */
27. 
    
28. /* Private typedef -----------------------------------------------------------*/
29. /* USER CODE BEGIN PTD */
30. 
    
31. /* USER CODE END PTD */
32. 
    
33. /* Private define ------------------------------------------------------------*/
34. /* USER CODE BEGIN PD */
35. /* USER CODE END PD */
36. 
    
37. /* Private macro -------------------------------------------------------------*/
38. /* USER CODE BEGIN PM */
39. 
    
40. /* USER CODE END PM */
41. 
    
42. /* Private variables ---------------------------------------------------------*/
43. SPI_HandleTypeDef hspi1;
44. 
    
45. /* USER CODE BEGIN PV */
46. 
    
47. /* USER CODE END PV */
48. 
    
49. /* Private function prototypes -----------------------------------------------*/
50. void SystemClock_Config(void);
51. static void MX_GPIO_Init(void);
52. static void MX_SPI1_Init(void);
53. /* USER CODE BEGIN PFP */
54. 
    
55. /* USER CODE END PFP */
56. 
    
57. /* Private user code ---------------------------------------------------------*/
58. /* USER CODE BEGIN 0 */
59. 
    
60. /* USER CODE END 0 */
61. 
    
62. /**
63. * @brief The application entry point.
64. * @retval int
65. */
66. int main(void)
67. {
68. /* USER CODE BEGIN 1 */
69. 
    
70. /* USER CODE END 1 */
71. 
    
72. /* MCU Configuration--------------------------------------------------------*/
73. 
    
74. /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
75. HAL_Init();
76. 
    
77. /* USER CODE BEGIN Init */
78. 
    
79. /* USER CODE END Init */
80. 
    
81. /* Configure the system clock */
82. SystemClock_Config();
83. 
    
84. /* USER CODE BEGIN SysInit */
85. 
    
86. /* USER CODE END SysInit */
87. 
    
88. /* Initialize all configured peripherals */
89. MX_GPIO_Init();
90. MX_SPI1_Init();
91. /* USER CODE BEGIN 2 */
92. 
    
93. /* USER CODE END 2 */
94. unsigned char patterns[16]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,
95. 0x07,0x7F,0x6F,0x77,0x7C,0x39,0x5E,0x79,0x71};
96. unsigned char i=0,temp;
97. /* Infinite loop */
98. /* USER CODE BEGIN WHILE */
99. while (1)
100. {
101. temp=~patterns[i];
102. HAL_SPI_Transmit(&hspi1,&temp,1,100);
103. HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4,GPIO_PIN_SET);
104. HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4,GPIO_PIN_RESET);
105. i++;
106. if(i>15) i=0;
107. HAL_Delay(500);
108. }
109. /* USER CODE END 3 */
110. }
111. 
     
112. /**
113. * @brief System Clock Configuration
114. * @retval None
115. */
116. void SystemClock_Config(void)
117. {
118. RCC_OscInitTypeDef RCC_OscInitStruct = {0};
119. RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
120. 
     
121. /** Initializes the RCC Oscillators according to the specified parameters
122. * in the RCC_OscInitTypeDef structure.
123. */
124. RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
125. RCC_OscInitStruct.HSIState = RCC_HSI_ON;
126. RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
127. RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
128. RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2;
129. RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;
130. if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
131. {
132. Error_Handler();
133. }
134. /** Initializes the CPU, AHB and APB buses clocks
135. */
136. RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
137. |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
138. RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
139. RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
140. RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
141. RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
142. 
     
143. if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
144. {
145. Error_Handler();
146. }
147. }
148. 
     
149. /**
150. * @brief SPI1 Initialization Function
151. * @param None
152. * @retval None
153. */
154. static void MX_SPI1_Init(void)
155. {
156. 
     
157. /* USER CODE BEGIN SPI1_Init 0 */
158. 
     
159. /* USER CODE END SPI1_Init 0 */
160. 
     
161. /* USER CODE BEGIN SPI1_Init 1 */
162. 
     
163. /* USER CODE END SPI1_Init 1 */
164. /* SPI1 parameter configuration*/
165. hspi1.Instance = SPI1;
166. hspi1.Init.Mode = SPI_MODE_MASTER;
167. hspi1.Init.Direction = SPI_DIRECTION_1LINE;
168. hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
169. hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
170. hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
171. hspi1.Init.NSS = SPI_NSS_SOFT;
172. hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;
173. hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
174. hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
175. hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
176. hspi1.Init.CRCPolynomial = 10;
177. if (HAL_SPI_Init(&hspi1) != HAL_OK)
178. {
179. Error_Handler();
180. }
181. /* USER CODE BEGIN SPI1_Init 2 */
182. 
     
183. /* USER CODE END SPI1_Init 2 */
184. 
     
185. }
186. 
     
187. /**
188. * @brief GPIO Initialization Function
189. * @param None
190. * @retval None
191. */
192. static void MX_GPIO_Init(void)
193. {
194. GPIO_InitTypeDef GPIO_InitStruct = {0};
195. 
     
196. /* GPIO Ports Clock Enable */
197. __HAL_RCC_GPIOA_CLK_ENABLE();
198. 
     
199. /*Configure GPIO pin Output Level */
200. HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
201. 
     
202. /*Configure GPIO pin : PA4 */
203. GPIO_InitStruct.Pin = GPIO_PIN_4;
204. GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
205. GPIO_InitStruct.Pull = GPIO_NOPULL;
206. GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
207. HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
208. 
     
209. }
210. 
     
211. /* USER CODE BEGIN 4 */
212. 
     
213. /* USER CODE END 4 */
214. 
     
215. /**
216. * @brief This function is executed in case of error occurrence.
217. * @retval None
218. */
219. void Error_Handler(void)
220. {
221. /* USER CODE BEGIN Error_Handler_Debug */
222. /* User can add his own implementation to report the HAL error return state */
223. __disable_irq();
224. while (1)
225. {
226. }
227. /* USER CODE END Error_Handler_Debug */
228. }
229. 
     
230. #ifdef USE_FULL_ASSERT
231. /**
232. * @brief Reports the name of the source file and the source line number
233. * where the assert_param error has occurred.
234. * @param file: pointer to the source file name
235. * @param line: assert_param error line source number
236. * @retval None
237. */
238. void assert_failed(uint8_t *file, uint32_t line)
239. {
240. /* USER CODE BEGIN 6 */
241. /* User can add his own implementation to report the file name and line number,
242. ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
243. /* USER CODE END 6 */
244. }
245. #endif /* USE_FULL_ASSERT */
246. 
     
247. /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

I connect the supply voltage of the SN74HC595N to +5VDC to get an appropriate brightness while the STM32 Blue Pill works at +3.3VDC only. Click here to download this example. 

 

STM32 Blue Pill HSPI1 and SN74HC595N LED Example

The SN74HC595N is an 8-bit serial-in-parallel out shift registers with latch outputs. It also has a serial data (DS) out pin for additional register cascading. This chip could operate at +3.3V level that could fit the STM32 micro-controller. For more information about using this chip, see this post.

SN74HC595N LED Shift

 

This chip use a three-wire SPI interface, MOSI, SCK and Enable Pin for SPI master mode half duplex micro-controller. I made my own test board for this chip that outputs to LEDs.

DIY SN74HC595N LED Test Board

 

The STM32CubeIDE has its code configure wizard enables the user to select any hardware and software setting of its micro-controller. Using HAL is very straight forward for writing code without using the micro-controller internal special registers.

The STM32F103C8T6 has two hardware SPI module, HSPI1 and HSPI2 that able to operate up to 16Mbits/s. 

I set the micro-controller to operate at 64MHz using its HSI and PLL. The SPI mode is Half Duplex Master with a 16MBits/s Baud Rate.

Clock Configuration

 

The SPI NSS pin is can not be use with the SN74HC595. So the Enable pin must be select by user's software. I use the PA4 pin for the SPI enable pin.

SPI and GPIO Setting

After the setting is finished click on generate code to get its skeleton program. The example below is a LED bar-graph that repeated endlessly. 

1. /* USER CODE BEGIN Header */
2. /**
3. ******************************************************************************
4. * @file : main.c
5. * @brief : Main program body
6. ******************************************************************************
7. * @attention
8. *
9. * <h2><center>&copy; Copyright (c) 2025 STMicroelectronics.
10. * All rights reserved.</center></h2>
11. *
12. * This software component is licensed by ST under BSD 3-Clause license,
13. * the "License"; You may not use this file except in compliance with the
14. * License. You may obtain a copy of the License at:
15. * opensource.org/licenses/BSD-3-Clause
16. *
17. ******************************************************************************
18. */
19. /* USER CODE END Header */
20. /* Includes ------------------------------------------------------------------*/
21. #include "main.h"
22. 
    
23. /* Private includes ----------------------------------------------------------*/
24. /* USER CODE BEGIN Includes */
25. 
    
26. /* USER CODE END Includes */
27. 
    
28. /* Private typedef -----------------------------------------------------------*/
29. /* USER CODE BEGIN PTD */
30. 
    
31. /* USER CODE END PTD */
32. 
    
33. /* Private define ------------------------------------------------------------*/
34. /* USER CODE BEGIN PD */
35. /* USER CODE END PD */
36. 
    
37. /* Private macro -------------------------------------------------------------*/
38. /* USER CODE BEGIN PM */
39. 
    
40. /* USER CODE END PM */
41. 
    
42. /* Private variables ---------------------------------------------------------*/
43. SPI_HandleTypeDef hspi1;
44. 
    
45. /* USER CODE BEGIN PV */
46. 
    
47. /* USER CODE END PV */
48. 
    
49. /* Private function prototypes -----------------------------------------------*/
50. void SystemClock_Config(void);
51. static void MX_GPIO_Init(void);
52. static void MX_SPI1_Init(void);
53. /* USER CODE BEGIN PFP */
54. 
    
55. /* USER CODE END PFP */
56. 
    
57. /* Private user code ---------------------------------------------------------*/
58. /* USER CODE BEGIN 0 */
59. 
    
60. /* USER CODE END 0 */
61. 
    
62. /**
63. * @brief The application entry point.
64. * @retval int
65. */
66. int main(void)
67. {
68. /* USER CODE BEGIN 1 */
69. 
    
70. /* USER CODE END 1 */
71. 
    
72. /* MCU Configuration--------------------------------------------------------*/
73. 
    
74. /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
75. HAL_Init();
76. 
    
77. /* USER CODE BEGIN Init */
78. 
    
79. /* USER CODE END Init */
80. 
    
81. /* Configure the system clock */
82. SystemClock_Config();
83. 
    
84. /* USER CODE BEGIN SysInit */
85. 
    
86. /* USER CODE END SysInit */
87. 
    
88. /* Initialize all configured peripherals */
89. MX_GPIO_Init();
90. MX_SPI1_Init();
91. /* USER CODE BEGIN 2 */
92. 
    
93. /* USER CODE END 2 */
94. uint8_t data=0, i=0;
95. /* Infinite loop */
96. /* USER CODE BEGIN WHILE */
97. while (1)
98. {
99. data|=(1<<i);
100. if(data==0xFF) data=0;
101. i++;
102. if(i>7) i=0;
103. HAL_SPI_Transmit(&hspi1,&data,1,10);
104. 
     
105. HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,0);
106. HAL_Delay(100);
107. HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,1);
108. }
109. /* USER CODE END 3 */
110. }
111. 
     
112. /**
113. * @brief System Clock Configuration
114. * @retval None
115. */
116. void SystemClock_Config(void)
117. {
118. RCC_OscInitTypeDef RCC_OscInitStruct = {0};
119. RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
120. 
     
121. /** Initializes the RCC Oscillators according to the specified parameters
122. * in the RCC_OscInitTypeDef structure.
123. */
124. RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
125. RCC_OscInitStruct.HSIState = RCC_HSI_ON;
126. RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
127. RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
128. RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2;
129. RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;
130. if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
131. {
132. Error_Handler();
133. }
134. /** Initializes the CPU, AHB and APB buses clocks
135. */
136. RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
137. |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
138. RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
139. RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
140. RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
141. RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
142. 
     
143. if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
144. {
145. Error_Handler();
146. }
147. }
148. 
     
149. /**
150. * @brief SPI1 Initialization Function
151. * @param None
152. * @retval None
153. */
154. static void MX_SPI1_Init(void)
155. {
156. 
     
157. /* USER CODE BEGIN SPI1_Init 0 */
158. 
     
159. /* USER CODE END SPI1_Init 0 */
160. 
     
161. /* USER CODE BEGIN SPI1_Init 1 */
162. 
     
163. /* USER CODE END SPI1_Init 1 */
164. /* SPI1 parameter configuration*/
165. hspi1.Instance = SPI1;
166. hspi1.Init.Mode = SPI_MODE_MASTER;
167. hspi1.Init.Direction = SPI_DIRECTION_1LINE;
168. hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
169. hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
170. hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
171. hspi1.Init.NSS = SPI_NSS_SOFT;
172. hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;
173. hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
174. hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
175. hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
176. hspi1.Init.CRCPolynomial = 10;
177. if (HAL_SPI_Init(&hspi1) != HAL_OK)
178. {
179. Error_Handler();
180. }
181. /* USER CODE BEGIN SPI1_Init 2 */
182. 
     
183. /* USER CODE END SPI1_Init 2 */
184. 
     
185. }
186. 
     
187. /**
188. * @brief GPIO Initialization Function
189. * @param None
190. * @retval None
191. */
192. static void MX_GPIO_Init(void)
193. {
194. GPIO_InitTypeDef GPIO_InitStruct = {0};
195. 
     
196. /* GPIO Ports Clock Enable */
197. __HAL_RCC_GPIOA_CLK_ENABLE();
198. 
     
199. /*Configure GPIO pin Output Level */
200. HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
201. 
     
202. /*Configure GPIO pin : PA4 */
203. GPIO_InitStruct.Pin = GPIO_PIN_4;
204. GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
205. GPIO_InitStruct.Pull = GPIO_NOPULL;
206. GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
207. HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
208. 
     
209. }
210. 
     
211. /* USER CODE BEGIN 4 */
212. 
     
213. /* USER CODE END 4 */
214. 
     
215. /**
216. * @brief This function is executed in case of error occurrence.
217. * @retval None
218. */
219. void Error_Handler(void)
220. {
221. /* USER CODE BEGIN Error_Handler_Debug */
222. /* User can add his own implementation to report the HAL error return state */
223. __disable_irq();
224. while (1)
225. {
226. }
227. /* USER CODE END Error_Handler_Debug */
228. }
229. 
     
230. #ifdef USE_FULL_ASSERT
231. /**
232. * @brief Reports the name of the source file and the source line number
233. * where the assert_param error has occurred.
234. * @param file: pointer to the source file name
235. * @param line: assert_param error line source number
236. * @retval None
237. */
238. void assert_failed(uint8_t *file, uint32_t line)
239. {
240. /* USER CODE BEGIN 6 */
241. /* User can add his own implementation to report the file name and line number,
242. ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
243. /* USER CODE END 6 */
244. }
245. #endif /* USE_FULL_ASSERT */
246. 
     
247. /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

Proteus VSM also has a model for the STM32 Blue Pill for simulation.

 

I tested on bread board with my SN74HC595N LED module. It works fine. We can connect the supply voltage pin of the SN74HC595N to +5VDC while the STM32 Blue pill operates at only +3.3VDC. Or even both of them connect to the +3.3VDC they still works.

SN74HC595N LED Bar-Graph

Now I made a little source code modification to make a simple LED shifting. 

1. while (1)
2. {
3. data=(1<<i);
4. //if(data==0xFF) data=0;
5. i++;
6. if(i>7) i=0;
7. HAL_SPI_Transmit(&hspi1,&data,1,10);
8. 
   
9. HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,0);
10. HAL_Delay(100);
11. HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,1);
12. }

SN74HC595N LED Shift

SN74HC595N LED Shift

 

Click here to download its source file.