pbio/platform/ev3: Pins for ev3 bluetooth module.

This adds the CTS and RTS pin definitions for UART2. It also configures
the "slow clock" input for the bluetooth module. Configures the BTnShutdn
gpio. Enables the ECAP functions in the PSC.

Author: jaguilar

lib/pbio/platform/ev3/platform.c

@@ -48,6 +48,7 @@
 #include <tiam1808/hw/hw_syscfg1_AM1808.h>
 #include <tiam1808/hw/hw_types.h>
 #include <tiam1808/hw/soc_AM1808.h>
+#include <tiam1808/ecap.h>
 #include <tiam1808/i2c.h>
 #include <tiam1808/psc.h>
 #include <tiam1808/timer.h>
@@ -784,8 +785,8 @@ void SystemInit(void) {
     IntChannelSet(SYS_INT_CCERRINT, 2);
     IntSystemEnable(SYS_INT_CCERRINT);
 
-
     PSCModuleControl(SOC_PSC_1_REGS, HW_PSC_GPIO, PSC_POWERDOMAIN_ALWAYS_ON, PSC_MDCTL_NEXT_ENABLE);
+    PSCModuleControl(SOC_PSC_1_REGS, HW_PSC_ECAP0_1_2, PSC_POWERDOMAIN_ALWAYS_ON, PSC_MDCTL_NEXT_ENABLE);
 
     // Must set the power enable bin before disabling the pull up on the power
     // pin below, otherwise the hub will power off.
@@ -795,11 +796,41 @@ void SystemInit(void) {
     HWREG(SOC_SYSCFG_1_REGS + SYSCFG1_PUPD_ENA) &= ~0xFFFFFFFF;
 
     // UART for Bluetooth. Other UARTS are configured by port module.
-    // TODO: Add CTS/RTS pins.
     const pbdrv_gpio_t bluetooth_uart_rx = PBDRV_GPIO_EV3_PIN(4, 19, 16, 1, 3);
     const pbdrv_gpio_t bluetooth_uart_tx = PBDRV_GPIO_EV3_PIN(4, 23, 20, 1, 2);
+    const pbdrv_gpio_t bluetooth_uart_cts = PBDRV_GPIO_EV3_PIN(0, 31, 28, 0, 8);
+    const pbdrv_gpio_t bluetooth_uart_rts = PBDRV_GPIO_EV3_PIN(0, 27, 24, 0, 9);
+    const pbdrv_gpio_t bluetooth_enable = PBDRV_GPIO_EV3_PIN(9, 27, 24, 4, 9);
     pbdrv_gpio_alt(&bluetooth_uart_rx, SYSCFG_PINMUX4_PINMUX4_19_16_UART2_RXD);
     pbdrv_gpio_alt(&bluetooth_uart_tx, SYSCFG_PINMUX4_PINMUX4_23_20_UART2_TXD);
+    pbdrv_gpio_alt(&bluetooth_uart_cts, SYSCFG_PINMUX0_PINMUX0_31_28_UART2_CTS);
+    pbdrv_gpio_alt(&bluetooth_uart_rts, SYSCFG_PINMUX0_PINMUX0_27_24_UART2_RTS);
+    pbdrv_gpio_alt(&bluetooth_enable, SYSCFG_PINMUX4_PINMUX4_27_24_GPIO1_1);
+    // For power saving, the bluetooth module disabled until its use is
+    // requested.
+    pbdrv_gpio_out_low(&bluetooth_enable);
+
+    // Configure ECAP2 to emit the slow clock signal for the bluetooth module.
+    ECAPOperatingModeSelect(SOC_ECAP_2_REGS, ECAP_APWM_MODE);
+    // Calculate the number of clock ticks the APWM period should last. Note
+    // that the following float operations are all constant and optimized away.
+    // APWM is clocked by sysclk2 by default.
+    // Target frequency is 32.767 kHz, see cc2560 datasheet.
+    const float period_cycles = SOC_SYSCLK_2_FREQ / 32767.0;
+    // APWM counter counts up to aprd inclusive.
+    const int aprd = period_cycles - 1;
+    const int cmp = aprd / 2;
+    ECAPAPWMCaptureConfig(SOC_ECAP_2_REGS, cmp, aprd);
+    // Set the polarity to active high. It doesn't matter which it is but for
+    // the sake of determinism we set it explicitly.
+    ECAPAPWMPolarityConfig(SOC_ECAP_2_REGS, ECAP_APWM_ACTIVE_HIGH);
+    // Disable input and output synchronization.
+    ECAPSyncInOutSelect(SOC_ECAP_2_REGS, ECAP_SYNC_IN_DISABLE, ECAP_SYNC_OUT_DISABLE);
+    // Start the counter running.
+    ECAPCounterControl(SOC_ECAP_2_REGS, ECAP_COUNTER_FREE_RUNNING);
+    // Set gp0[7] to output the ECAP2 APWM signal.
+    const pbdrv_gpio_t bluetooth_slow_clock = PBDRV_GPIO_EV3_PIN(1, 3, 0, 0, 7);
+    pbdrv_gpio_alt(&bluetooth_slow_clock, SYSCFG_PINMUX1_PINMUX1_3_0_ECAP2);
 
     // Read the EV3 Bluetooth MAC address from the I2C boot EEPROM