Talking to EPD now

Work in progress.

2 files changed, 87 insertions, 29 deletions

diff --git a/laser-tag software/epaper.c b/laser-tag software/epaper.c
index d4e7d81..df3e9a1 100644
--- a/laser-tag software/epaper.c
+++ b/laser-tag software/epaper.c
@@ -1,18 +1,18 @@
 #include "fsl_gpio_driver.h"
 #include "fsl_spi_master_driver.h"
 
-static const gpio_output_pin_user_config_t pinReset = {
-    .pinName = GPIO_MAKE_PIN(GPIOA_IDX, 20),
-    .config.outputLogic = 0, // XXX
-};
-
 static const gpio_output_pin_user_config_t pinDischarge = {
     .pinName = GPIO_MAKE_PIN(GPIOA_IDX, 19),
     .config.outputLogic = 0,
 };
 
+static const gpio_output_pin_user_config_t pinCS = {
+    .pinName = GPIO_MAKE_PIN(GPIOD_IDX, 4),
+    .config.outputLogic = 1,
+};
+
 static const spi_master_user_config_t spiConfig = {
-    .bitsPerSec = 4000000, /* 4 MHz, max is 20 MHz */
+    .bitsPerSec = 2000000, /* 2 MHz, max is 20 MHz */
     .polarity = kSpiClockPolarity_ActiveHigh,
     .phase = kSpiClockPhase_FirstEdge,
     .direction = kSpiMsbFirst,
@@ -21,46 +21,93 @@ static const spi_master_user_config_t spiConfig = {
 
 static spi_master_state_t spiState;
 
-extern void led(uint8_t red, uint8_t green, uint8_t blue);
-
 void EPD_Init()
 {
     PORT_HAL_SetMuxMode(g_portBase[GPIOA_IDX], 19, kPortMuxAsGpio);
     PORT_HAL_SetMuxMode(g_portBase[GPIOA_IDX], 20, kPortMuxAsGpio);
-    PORT_HAL_SetMuxMode(g_portBase[GPIOD_IDX], 4, kPortMuxAlt2);
+    PORT_HAL_SetMuxMode(g_portBase[GPIOD_IDX], 4, kPortMuxAsGpio);
     PORT_HAL_SetMuxMode(g_portBase[GPIOD_IDX], 5, kPortMuxAlt2);
     PORT_HAL_SetMuxMode(g_portBase[GPIOD_IDX], 6, kPortMuxAlt2);
     PORT_HAL_SetMuxMode(g_portBase[GPIOD_IDX], 7, kPortMuxAlt2);
-    GPIO_DRV_OutputPinInit(&pinReset);
     GPIO_DRV_OutputPinInit(&pinDischarge);
+    GPIO_DRV_OutputPinInit(&pinCS);
     SPI_DRV_MasterInit(1, &spiState);
     uint32_t calculatedBaudRate;
     SPI_DRV_MasterConfigureBus(1, &spiConfig, &calculatedBaudRate);
 }
 
-void EPD_Draw()
+void EPD_WriteCommandBuffer(uint8_t index, uint8_t *data, size_t length)
+{
+    uint8_t tx[3] = { 0x70, index, 0x72 };
+
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 0);
+    SPI_DRV_MasterTransferBlocking(1, NULL, tx, NULL, 2, 1);
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 1);
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 0);
+    SPI_DRV_MasterTransferBlocking(1, NULL, &tx[2], NULL, 1, 1);
+    SPI_DRV_MasterTransferBlocking(1, NULL, data, NULL, length, 1);
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 1);
+}
+
+void EPD_WriteCommandByte(uint8_t index, uint8_t data)
 {
-    /* Reset */
-    GPIO_DRV_WritePinOutput(pinReset.pinName, 0);
-    int i;
-    for(i = 0; i < 0xffff; ++i);
-    //GPIO_DRV_WritePinOutput(pinReset.pinName, 1);
-
-    uint8_t tx[2], rx[2];
-
-    tx[0] = 0x71;
-    tx[1] = 0x00;
-    SPI_DRV_MasterTransferBlocking(1, NULL, tx, rx, 2, 1);
-    SPI_DRV_MasterTransferBlocking(1, NULL, tx, rx, 2, 1);
-    if ((rx[1] & 0x0f) != 0x02) {
-        led(0xff, 0x00, 0x00);
-    } else {
-        led(0x00, 0xff, 0x00);
+    EPD_WriteCommandBuffer(index, &data, 1);
+}
+
+uint8_t EPD_ReadCommand(uint8_t index)
+{
+    uint8_t tx[4] = { 0x70, index, 0x73, 0x00 };
+    uint8_t rx[2];
+
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 0);
+    SPI_DRV_MasterTransferBlocking(1, NULL, tx, NULL, 2, 1);
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 1);
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 0);
+    SPI_DRV_MasterTransferBlocking(1, NULL, &tx[2], rx, 2, 1);
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 1);
+    return rx[1];
+}
+
+uint8_t EPD_ReadCogID()
+{
+    uint8_t tx[2] = { 0x71, 0x00 };
+    uint8_t rx[2];
+
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 0);
+    SPI_DRV_MasterTransferBlocking(1, NULL, tx, rx, sizeof tx, 1);
+    GPIO_DRV_WritePinOutput(pinCS.pinName, 1);
+    return rx[1];
+}
+
+int EPD_Draw()
+{
+    /* read the COG ID */
+    uint8_t id = EPD_ReadCogID();
+    if ((id & 0x0f) != 0x02) {
+        return -1;
     }
 
+    /* disable OE */
+    EPD_WriteCommandByte(0x02, 0x40);
+
+    /* check breakage */
+    uint8_t broken_panel = EPD_ReadCommand(0x0f);
+    if (0x00 == (0x80 & broken_panel)) {
+        return -2;
+    }
+
+    /* power saving mode */
+    EPD_WriteCommandByte(0x0b, 0x02);
+
     /* Shutdown */
     GPIO_DRV_WritePinOutput(pinDischarge.pinName, 1);
     GPIO_DRV_WritePinOutput(pinDischarge.pinName, 0);
+    return 0;
+}
+
+void EPD_Deinit()
+{
+    SPI_DRV_MasterDeinit(1);
 }
 
 /* vim: set expandtab ts=4 sw=4: */
diff --git a/laser-tag software/main.c b/laser-tag software/main.c
index a2dc21d..99b8812 100755
--- a/laser-tag software/main.c
+++ b/laser-tag software/main.c
@@ -237,7 +237,8 @@ static flexio_shifter_config_t g_shifterConfig = {
 
 
 extern void EPD_Init();
-extern void EPD_Draw();
+extern int EPD_Draw();
+extern void EPD_Deinit();
 
 ///////
 // Code
@@ -529,7 +530,17 @@ int main (void)
     EPD_Init();
 
     /* Draw something */
-    EPD_Draw();
+    int ret = EPD_Draw();
+    if (ret == -1) {
+        led(0xff, 0x00, 0x00);
+    } else if (ret == -2) {
+        led(0xff, 0xff, 0x00);
+    } else {
+        led(0x00, 0xff, 0x00);
+    }
+
+    /* Deinit so we can mess around on the bus pirate */
+    EPD_Deinit();
 
     /* We're done, everything else is triggered through interrupts */
     for(;;) {