###### tags: `Embedded`

# STM32F1 開發紀錄

## Motion Model

## EEPROM

HAL_StatusTypeDef res;
uint8_t buf[] = "hello world! eeprom";
uint8_t buf_read[100] = {0};

while (HAL_I2C_IsDeviceReady(&hi2c1, 0xa0, 5, 1000) != HAL_OK)
    ;
res = HAL_I2C_IsDeviceReady(&hi2c1, 0xa0, 5, 1000);
debug_print("HAL_I2C_IsDeviceReady: %d", res);

uint16_t dm = 5566, dm_read;
res = HAL_I2C_Mem_Write(&hi2c1, 0xA0, 4, I2C_MEMADD_SIZE_16BIT,
                      (uint8_t *)&dm, 2, 1000);
debug_print("res: %d", res);
HAL_Delay(10);

res = HAL_I2C_Mem_Read(&hi2c1, 0xA0, 4, I2C_MEMADD_SIZE_16BIT,
                     (uint8_t *)&dm_read, 2, 1000);
debug_print("res: %d", res);

EEPROM_Write(1, 10, buf, sizeof buf);
EEPROM_Read(1, 10, buf_read, sizeof buf);
uint16_t data = 12;
uint16_t rdata = 0;
module_eeprom_save_dm(103, data);
HAL_Delay(10);
rdata = module_eeprom_read_dm(103);
fxcomm1_dm.target_spd = rdata;
debug_print("fxcomm1_dm.target_spd: %u", fxcomm1_dm.target_spd);

## FRAM

volatile uint16_t *addr = (void *)(SRAM_BEGIN_ADDR + 100);
// *addr = 5566;
for (int i = -5; i < 5; i++) {
    debug_print("addr: %p, value: %u", (addr + i), *(addr + i));
}

## Servo Motor

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:::spoiler
校ㄌ
:::

## Modbus

:::danger
錯誤的讀取 (使用HEXIN 485轉232 讀取的資料)

FB F9 FF E7 FF FD 77 8B CD

:::

### Modbus Endianness

Modbus 在規格中有指定任何 word (16bit) 的格式一定是 big endian，==也就是 byte order 是 big endian。==

所以我們可以預期任何正確實作的 Modbus middleware 會將讀到的 word，轉換成計算平台上的格式。例如 [Modbus-STM32-HAL-FreeRTOS](https://github.com/alejoseb/Modbus-STM32-HAL-FreeRTOS/issues?q=endian) 此 Modbus 實作會將 big endian 轉成 little endian。

(stm32 Cortex-M 微處理器都是使用 little endian)

:::info

uint16_t word(uint8_t H, uint8_t L)
{
	bytesFields W;
	W.u8[0] = L;
	W.u8[1] = H;

	return W.u16[0];
}

https://github.com/alejoseb/Modbus-STM32-HAL-FreeRTOS/blob/5d9b35020ecb7e03ed831a41799a8cb378e83a6f/MODBUS-LIB/Src/Modbus.c#L1440-L1447
:::

但是對於更大的資料格式如 dword (32bit) 則沒有規定，因此，必須先查看從站或主站通訊中關於 word order 的設定。

以我的從站為例

Word order: Little endian
Byte order: Big endian

### RS485 Connection/Hardware

Also check Fail safe bias
https://www.edaboard.com/threads/max3485-with-usb-rs-485.400038/

- https://www.youtube.com/watch?v=bt9Px51eP6s&t=499s&ab_channel=TexasInstruments
- https://e2e.ti.com/blogs_/b/analogwire/posts/rs-485-basics-when-termination-is-necessary-and-how-to-do-it-properly

### Modbus References
- https://www.csimn.com/CSI_pages/Modbus101.html
- https://ipc2u.com/articles/knowledge-base/modbus-rtu-made-simple-with-detailed-descriptions-and-examples/
- https://ozeki.hu/p_5854-modbus-rtu.html
- https://library.e.abb.com/public/ac691e6f68a24893b1c9e0f52db07e45/AN00198_Integrated_Modbus_support_RevE_EN.pdf
- https://ithelp.ithome.com.tw/articles/10282249