Other Parts Discussed in Thread: SYSCONFIG
Tool/software:
Hello all,
I am having trouble reading register values from the MCP23S17 SPI expander we are using with our AM6421B processor. To start with, we are using the MCSPI TI driver to address our SPI devices, including the MCP23S17. The main function for doing this comes from the iolink_master_demo in the industrial comms SDK version 9.2.0.8 named iolm_port_spi.c. This is the function:
int32_t IOLM_SPI_mcspiTransfer(
uint32_t mcspiInstance,
uint32_t mcspiChannel,
uint32_t mcspiDataSize,
uint8_t *pTxData,
uint8_t *pRxData,
uint32_t lengthInBytes)
{
uint32_t lengthInBits;
uint32_t lengthInWords;
int32_t error;
MCSPI_Transaction *pTransaction;
// check the platform
MCSPI_Transaction transaction;
pTransaction = &transaction;
if ((mcspiInstance >= CONFIG_MCSPI_NUM_INSTANCES) || (mcspiChannel >= MCSPI_MAX_NUM_CHANNELS)
|| (gMcspiConfig[mcspiInstance].object == NULL))
{
error = SystemP_FAILURE;
OSAL_error(
__FILE__,
__LINE__,
OSAL_eERR_INVALIDSTATE,
true,
1,
"SPI setup does not match sysCfg SPI setup or SPI init failed.\r\n");
goto laExit;
}
/* convert length in bytes to frames with channel/instance configuration specific width */
lengthInBits = lengthInBytes * 8;
lengthInWords = lengthInBits / mcspiDataSize;
if ((lengthInBits % mcspiDataSize) > 0)
{
lengthInWords++;
}
MCSPI_Transaction_init(pTransaction);
// load data to the cache
if (MCSPI_OPER_MODE_DMA
== ((MCSPI_Config *)gMcspiConfig[mcspiInstance].object->handle)->attrs->operMode)
{
CacheP_wb(pTxData, lengthInBytes, CacheP_TYPE_ALLD);
CacheP_wbInv(pRxData, lengthInBytes, CacheP_TYPE_ALLD);
}
pTransaction->channel = mcspiChannel;
pTransaction->txBuf = pTxData;
pTransaction->rxBuf = pRxData;
pTransaction->dataSize = mcspiDataSize;
pTransaction->count = lengthInWords;
pTransaction->csDisable = TRUE;
error = MCSPI_transfer(gMcspiConfig[mcspiInstance].object->handle, pTransaction);
laExit:
return error;
}If this is not the right way to address this device, then that would be a good place to start for fixing my issues. However, that's what I have been using thus far.
I was unsure how to "set up" the device on initialization. It is my understanding that most of this is done in SysConfig generated code, but from looking elsewhere online it appeared there would also be initialization required to use the address pins (A2, A1, A0). On our board, we are using pin A2 as an address pin. Therefore, I have the following code to initialize the IOCON register to enable IOCON.HAEN:
// Write to IOCON.HAEN
// A2 is set here in the address - not sure if this is correct. 0A is
// the register address of IOCON when IOCON.BANK = 0.
uint16_t txBuf[2] = {0x480Au, 0u};
// Intended to set bit 3 in IOCON.
uint8_t u8txBuf = 0x08u;
int32_t error = SystemP_SUCCESS;
error = IOLM_SPI_mcspiTransfer(CONFIG_MCSPI_SPI1,
MCSPI_CHANNEL_0,
16u,
txBuf,
NULL,
4u);
DebugP_assert(error == SystemP_SUCCESS);
error = IOLM_SPI_mcspiTransfer(CONFIG_MCSPI_SPI1,
MCSPI_CHANNEL_0,
8u,
&utx8Buf,
NULL,
1u);
DebugP_assert(error == SystemP_SUCCESS);Next, I try to read from the GPIOA register with the following code:
// 0x49 = address pin A2 set, and read
// 0x12 = address of GPIOA register when IOCON.BANK = 0.
uint16_t txBuf = 0x4912;
uint16_t rxBuf = 0u;
int32_t error = SystemP_SUCCESS;
error = IOLM_SPI_mcspiTransfer(CONFIG_MCSPI_SPI1,
MCSPI_CHANNEL_0,
16u,
&txBuf,
&rxBuf,
3u);
DebugP_assert(error == SystemP_SUCCESS);Doing this results in reading the value "0xff 0xff". This is the expected value for reading the IODIR register, but that is at address register 0x0. We are attempting to address 0x12, which should just contain "0x1" because we are powering pin 2 on the port of our board. The value returned is the same whether or not we try to initialize IOCON.HAEN, which would lead me to believe that we might be doing that incorrectly.
This is the SysCfg we are using for MCSPI - the SPI expander (MCP23S17) is on CS0.
mcspi1.intrEnable = "POLLED"; mcspi1.mode = "MULTI_CONTROLLER"; mcspi1.$name = "CONFIG_MCSPI_SPI1"; mcspi1.advanced = true; mcspi1.SPI.$assign = "SPI1"; mcspi1.SPI.CLK.$assign = "SPI1_CLK"; mcspi1.SPI.D0.rx = false; mcspi1.SPI.D0.$assign = "SPI1_D0"; mcspi1.SPI.D1.$assign = "SPI1_D1"; mcspi1.child.$name = "drivers_mcspi_v0_mcspi_v0_template0"; mcspi1.mcspiChannel.create(2); mcspi1.mcspiChannel[0].$name = "CONFIG_MCSPI_SPI1_CS0"; mcspi1.mcspiChannel[0].advanced = true; mcspi1.mcspiChannel[0].CSn.rx = false; mcspi1.mcspiChannel[0].CSn.$assign = "SPI1_CS0"; mcspi1.mcspiChannel[1].$name = "CONFIG_MCSPI_SPI1_CS1"; mcspi1.mcspiChannel[1].advanced = true; mcspi1.mcspiChannel[1].bitRate = 20000000; mcspi1.mcspiChannel[1].CSn.rx = false; mcspi1.mcspiChannel[1].CSn.$assign = "SPI1_CS1";
My question is - is there something I'm missing when addressing this SPI device? Is there some initialization I haven't done that needs to be done in order to properly read the registers? I apologize for such a long post, but we have been at this for a while and the most progress we got was reading "0xff 0xff" from the device.
Thanks for any help,
Owen
