尊敬的堆栈溢出用户:
我用一个主设备和一个由10个从设备组成的网络构建了一个设备。它们都通过4线spi通信。现在我正在为两个董事会编写程序,他们似乎都不起作用,我没有得到预期的回应。
我有一个主板,和10个相同的从主板。协议很简单,就像spi一样,任何事务都由主设备发起,并发送命令。然后,所选从机接收一个预先调整的命令,将忙标志引脚设置为高,并检查它是否有效。解析命令后,将释放busy bin,如果命令有效,则向master发送与接收到的字节相同的字节,否则将发送错误标记。之后,执行任何必要的数据交换。我试过将IO配置为常规端口F及其替代功能,也试过在每次事务后重置SPI外围设备,但似乎没有任何效果。
这就是我得到的:
https://imgur.com/a/MICEx2f
频道分别从顶部开始:
mosi,miso,clk和busy flag。不管怎样,我都得不到奴隶的回应。该命令被正确解释(来自uart的调试数据),但是没有返回任何内容。
这是从设备代码的spi部分:
uint8_t spi_sendrecv(uint8_t byte)
{
// poczekaj az bufor nadawczy bedzie wolny
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI1, byte);
// poczekaj na dane w buforze odbiorczym
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
return SPI_I2S_ReceiveData(SPI1);
}
uint8_t SPI_get_cmd_ack(void)
{
uint8_t cmd;
uint8_t valid_flag;
//In cas if the BF pin was left high
BF_OUT_low();
//Let's wait for some data
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
cmd = SPI_I2S_ReceiveData(SPI1);
//cmd = SPI_get_command();
//Check the cmd
BF_OUT_high();
valid_flag = SPI_check_for_valid_cmd(cmd);
//SPI_reset_flush();
BF_OUT_low();
if(valid_flag == CMD_RET_STATUS_VALID)
{
spi_sendrecv(cmd);
return cmd;
}
else
{
spi_sendrecv(CMD_ERROR);
return CMD_ERROR;
}
}
这是主要部分:
//Sends a command to a slave device
//Param1: slave device no, from 0 to 9
//Param2: command to send
//Retval: command send success or failure:
//DATA_TRANSFER_OK or DATA_TRANSFER_ERR
uint8_t SPI_send_command(uint8_t slave_no, uint8_t cmd)
{
uint8_t cnt = 0;
uint8_t rx_cmd;
//SPI_reset();
//Select the correct slave
SPI_select_slave(0);
delay_ms(0);
SPI_select_slave(slave_no);
delay_ms(0);
//Transmit the cmd
SPI_sendrecv(cmd);
//SPI_reset();
//Wait for the busy flag indication
while(SPI_get_busy_flag(slave_no) == Bit_RESET)
{
if(cnt < SPI_RETRY_COUNT)
{
++cnt;
delay_ms(1);
}
else
{
SPI_select_slave(0);
return DATA_TRANSFER_ERR;
}
}
//Same for the busy flag on:
while (SPI_get_busy_flag(slave_no) == Bit_SET)
{
if(cnt < SPI_RETRY_COUNT)
{
++cnt;
delay_ms(1);
}
else
{
SPI_select_slave(0);
return DATA_TRANSFER_ERR;
}
}
rx_cmd = SPI_sendrecv(0);
//SPI_reset();
if(rx_cmd == cmd) return DATA_TRANSFER_OK;
else return DATA_TRANSFER_ERR;
}
下面是代码的初始化部分,slave和master分别是:
void SPI_init(void)
{
GPIO_InitTypeDef SPI_GPIO;
SPI_InitTypeDef SPI;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB | RCC_AHBPeriph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
//GPIOA5 SCK
//GPIOA6 MISO
//GPIOA7 MOSI
SPI_GPIO.GPIO_Mode = GPIO_Mode_AF;
SPI_GPIO.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
SPI_GPIO.GPIO_PuPd = GPIO_PuPd_DOWN;
SPI_GPIO.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_Init(GPIOA, &SPI_GPIO);
SPI_GPIO.GPIO_Pin = GPIO_Pin_15;
SPI_GPIO.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &SPI_GPIO);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource15, GPIO_AF_SPI1);
//Busy flag
SPI_GPIO.GPIO_Mode = GPIO_Mode_OUT;
SPI_GPIO.GPIO_OType = GPIO_OType_PP;
SPI_GPIO.GPIO_Pin = GPIO_Pin_5;
GPIO_Init(GPIOC, &SPI_GPIO);
/*SPI_GPIO.GPIO_Mode = GPIO_Mode_IN;
SPI_GPIO.GPIO_PuPd = GPIO_PuPd_UP;
SPI_GPIO.GPIO_Pin = GPIO_Pin_15;
GPIO_Init(GPIOA, &SPI_GPIO);*/
SPI.SPI_CPHA = SPI_CPHA_1Edge;
SPI.SPI_CPOL = SPI_CPOL_Low;
SPI.SPI_DataSize = SPI_DataSize_8b;
SPI.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI.SPI_FirstBit = SPI_FirstBit_MSB;
SPI.SPI_Mode = SPI_Mode_Slave;
SPI.SPI_NSS = SPI_NSS_Hard;
SPI_Init(SPI1, &SPI);
SPI_Cmd(SPI1, ENABLE);
SPI_aux_tim_conf();
}
static void SPI_IO_conf(void)
{
//Struct
GPIO_InitTypeDef SPI_IO;
//CLK
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOE, ENABLE);
//Conf
SPI_IO.GPIO_Mode = GPIO_Mode_AF;
//5 - SCK, 6 - MISO, 7- MOSI
SPI_IO.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7 | GPIO_Pin_6;
SPI_IO.GPIO_PuPd = GPIO_PuPd_DOWN;
SPI_IO.GPIO_OType = GPIO_OType_PP;
SPI_IO.GPIO_Speed = GPIO_Speed_25MHz;
//Init
GPIO_Init(GPIOA, &SPI_IO);
//Connect to SPI periph
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
//For busy flag checking
SPI_IO.GPIO_Mode = GPIO_Mode_IN;
SPI_IO.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11 |GPIO_Pin_12 |GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
SPI_IO.GPIO_PuPd = GPIO_PuPd_DOWN;
SPI_IO.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_Init(GPIOE, &SPI_IO);
SPI_IO.GPIO_Pin = GPIO_Pin_10;
GPIO_Init(GPIOB, &SPI_IO);
}
static void SPI_periph_conf(void)
{
//Struct
SPI_InitTypeDef SPI_conf;
//CLK
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
//Conf
//SysClk = 84000000
//84/64 = 1,3125MHz
SPI_conf.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_128;
SPI_conf.SPI_CPHA = SPI_CPHA_1Edge;
SPI_conf.SPI_CPOL = SPI_CPOL_Low;
//SPI_conf.SPI_CRCPolynomial =
SPI_conf.SPI_DataSize = SPI_DataSize_8b;
SPI_conf.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_conf.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_conf.SPI_Mode = SPI_Mode_Master;
SPI_conf.SPI_NSS = SPI_NSS_Soft;
//Conf, enable
SPI_Init(SPI1, &SPI_conf);
SPI_Cmd(SPI1, ENABLE);
//SPI_Cmd(SPI1, DISABLE);
}
从示波图上可以看到,从机没有响应,预期响应与主机在前一个周期发送的命令相同。例如,我发送一个0x01存在命令,从机应该用相同的字节响应,之后,应该发生任何其他交换,这些交换尚未实现。
谨致问候,马雷克
最佳答案
从你的图片上看,发送数据后clk保持在低位。在spi中,主人是时钟的唯一管理者。
从AA>
忙标志
此bsy标志由硬件设置和清除(写入此标志无效)。bsy标志表示spi的通信层的状态。
设置bsy时,表示spi正忙着通信。在主模式/双向接收模式(mstr=1和bdm=1和bdoe=0)中有一个例外,在接收期间bsy标志保持低。
如果软件要禁用SPI并进入暂停模式(或禁用外围时钟),则BSY标志可用于检测传输结束。这样可以避免破坏最后一次传输。为此,必须严格遵守以下程序。
bsy标志对于避免多主机系统中的写入冲突也很有用。
在传输开始时设置bsy标志,除了主模式/双向接收模式(mstr=1和bdm=1和bdoe=0)。
已清除:
传输完成时(如果通信是连续的,则在主模式下除外)
当发生主模式故障(modf=1)时,SPI被禁用
当通信不连续时,每次通信之间的bsy标志是低的。
当通信持续时:
在主模式下,bsy标志在所有传输期间都保持高
在从模式下,每次传输之间的一个spi时钟周期内bsy标志变低
注意:不要使用bsy标志来处理每次数据传输或接收。最好改用txe和rxne标志
所以我认为你在发送数据后在主机中等待busy标志可以无限期锁定。试试这个(代码使用普通的cmsis,但应该可以理解):
GPIOB->BSRR |= GPIO_BSRR_BR6; //slave select
while(! (SPI1->SR & SPI_SR_TXE)); //wait for Tx buffer empty
SPI1->DR = 0x01; //send 0x01
while(! (SPI1->SR & SPI_SR_RXNE)); //wait for Rx buffer not empty (receive 0x0 sent by the slave during our sending 0x01 since it's 4-wire SPI)
uint8_t tmp = SPI1->DR; //we don't need that value, but need to read DR in order to reset RXNE flag
SPI1->DR = 0x0; //we need to trigger send in order to receive
while(! (SPI1->SR & SPI_SR_RXNE)); //wait for Rx buffer not empty (our response)
response = SPI1->DR;
while(SPI1->SR & SPI_SR_BSY); //now we can wait for SPI to end communications
GPIOB->BSRR |= GPIO_BSRR_BS6; //slave deselect
关于c - STM32,主设备和从设备彼此不响应,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/55587289/