Synopsis
int sub_sdio_transfer( sub_handle hndl, char* out_buf, char* in_buf,
int out_sz, int in_sz, int ss_config )
Perform 3-Wire compatible SPI master transaction like one shown below.
1.SS changes according to ss_config parameter.
2.out_sz bytes are transmitted via MOSI. MOSI will be in output state during transfer.
3.MOSI state is changed to HiZ after last bit transmitted. If required SS changes.
4.in_sz bytes received from MISO input. MOSI left in HiZ state.
5.SS changes according to ss_config parameter
SPI Clock - SCK phase and polarity can be configured with sub_spi_config.
Above implementation of SPI transaction allows using of the SUB-20 as 3-Wire SPI master. In this case connection to 3-Wire device should be as following:
Parameters
•out_buf - Output data buffer.
•in_buf - Input buffer to store read data.
•out_sz - Number of bytes to transmit in range 0..60.
•in_sz - Number of bytes to receive in range 0..60.
•ss_config - Determines selection and operation of SS pin. ss_config value must be created with macro
SS_CONF(SS_N,SS_MODE) ,
where SS_N is SS pin number and SS_MODE is one of the following flags:
SS_HL |
SS goes high and stays high during transmit stage, after that it goes low |
SS_HI |
SS goes high and stays high during entire transaction (transmit and receive), after that it goes low |
SS_LH |
SS goes low and stays low during transmit stage, after that it goes high |
SS_LO |
SS goes low and stays low during entire transaction (transmit and receive), after that it goes high |
SS_HiZ |
SS stays in HiZ mode (Except SS0) |
If ss_config is zero there will be no SS activity (changes).
Return value
On success function returns 0. Otherwise error code.
Example
/* Transmit one byte and receive 3 bytes */
/* SS1 goes low during transaction */
sub_sdio_transfer( hndl, out_buf, in_buf, 1, 3, SS_CONF(1,SS_LO) );
Compatibility
FW version |
0.1.9 or grater |
Library version |
0.1.12.11 or grater |