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Corrected SPI CPOL/CPHA relationships 

* Corrected CPOL/CPHA relationships

* Simplified to remove duplicated code

* Removed comments about when MISO is sampled. ESP seems to sample MISO on same clock edge as when MOSI is set.
This commit is contained in:
Jason Follas 2016-04-02 13:26:07 -04:00 committed by Arnim Läuger
parent a1ffe2e9fd
commit e16204d4f4
1 changed files with 12 additions and 5 deletions
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17
app/driver/spi.c
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@ -72,18 +72,25 @@ void spi_master_init(uint8 spi_no, unsigned cpol, unsigned cpha, uint32_t clock_
SET_PERI_REG_MASK(SPI_USER(spi_no), SPI_CS_SETUP|SPI_CS_HOLD|SPI_RD_BYTE_ORDER|SPI_WR_BYTE_ORDER|SPI_DOUTDIN); SET_PERI_REG_MASK(SPI_USER(spi_no), SPI_CS_SETUP|SPI_CS_HOLD|SPI_RD_BYTE_ORDER|SPI_WR_BYTE_ORDER|SPI_DOUTDIN);
//set clock polarity (Reference: http://bbs.espressif.com/viewtopic.php?f=49&t=1570) // set clock polarity (Reference: http://bbs.espressif.com/viewtopic.php?f=49&t=1570)
// phase is dependent on polarity. See Issue #1161
if (cpol == 1) { if (cpol == 1) {
SET_PERI_REG_MASK(SPI_PIN(spi_no), SPI_IDLE_EDGE); SET_PERI_REG_MASK(SPI_PIN(spi_no), SPI_IDLE_EDGE);
} else { } else {
CLEAR_PERI_REG_MASK(SPI_PIN(spi_no), SPI_IDLE_EDGE); CLEAR_PERI_REG_MASK(SPI_PIN(spi_no), SPI_IDLE_EDGE);
} }
//set clock phase //set clock phase
if (cpha == 1) { if (cpha == cpol) {
SET_PERI_REG_MASK(SPI_USER(spi_no), SPI_CK_OUT_EDGE|SPI_CK_I_EDGE); // Mode 3: MOSI is set on falling edge of clock
// Mode 0: MOSI is set on falling edge of clock
CLEAR_PERI_REG_MASK(SPI_USER(spi_no), SPI_CK_OUT_EDGE);
SET_PERI_REG_MASK(SPI_USER(spi_no), SPI_CK_I_EDGE);
} else { } else {
CLEAR_PERI_REG_MASK(SPI_USER(spi_no), SPI_CK_OUT_EDGE|SPI_CK_I_EDGE); // Mode 2: MOSI is set on rising edge of clock
// Mode 1: MOSI is set on rising edge of clock
SET_PERI_REG_MASK(SPI_USER(spi_no), SPI_CK_OUT_EDGE);
CLEAR_PERI_REG_MASK(SPI_USER(spi_no), SPI_CK_I_EDGE);
} }
CLEAR_PERI_REG_MASK(SPI_USER(spi_no), SPI_FLASH_MODE|SPI_USR_MISO|SPI_USR_ADDR|SPI_USR_COMMAND|SPI_USR_DUMMY); CLEAR_PERI_REG_MASK(SPI_USER(spi_no), SPI_FLASH_MODE|SPI_USR_MISO|SPI_USR_ADDR|SPI_USR_COMMAND|SPI_USR_DUMMY);