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Code Issues Wiki Activity

Detect MAX/AT7456 chip existence

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This commit is contained in:
jflyper 2019-09-28 04:05:34 +09:00
parent 1c8d41b952
commit e821fec341
1 changed files with 23 additions and 2 deletions
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25
src/main/drivers/max7456.c
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@ -439,12 +439,33 @@ bool max7456Init(const max7456Config_t *max7456Config, const vcdProfile_t *pVcdP
spiBusSetInstance(busdev, spiInstanceByDevice(SPI_CFG_TO_DEV(max7456Config->spiDevice)));
// Detect device type by writing and reading CA[8] bit at CMAL[6].
// Do this at half the speed for safety.
// Detect MAX7456 existence and device type. Do this at half the speed for safety.
// Detect MAX7456 and compatible device by reading OSDM (OSD Insertion MUX) register.
// This register is not modified in this driver, therefore ensured to remain at its default value (0x1B).
spiSetDivisor(busdev->busdev_u.spi.instance, MAX7456_SPI_CLK * 2);
__spiBusTransactionBegin(busdev);
uint8_t osdm = max7456Send(MAX7456ADD_OSDM|MAX7456ADD_READ, 0xff);
if (osdm != 0x1B) {
IOConfigGPIO(busdev->busdev_u.spi.csnPin, IOCFG_IPU);
return false;
}
__spiBusTransactionEnd(busdev);
// At this point, we can claim the ownership of the CS pin
IOInit(busdev->busdev_u.spi.csnPin, OWNER_OSD_CS, 0);
// Detect device type by writing and reading CA[8] bit at CMAL[6].
// This is a bit for accessing second half of character glyph storage, supported only by AT variant.
__spiBusTransactionBegin(busdev);
max7456Send(MAX7456ADD_CMAL, (1 << 6)); // CA[8] bit
if (max7456Send(MAX7456ADD_CMAL|MAX7456ADD_READ, 0xff) & (1 << 6)) {