JTAG: Restore CPLD pin config functions, leave pins in pull-only state when not actively operating.

firmware/common/cpld_jtag.c

@@ -29,6 +29,75 @@ static refill_buffer_cb refill_buffer;
 static uint32_t xsvf_buffer_len, xsvf_pos;
 static unsigned char* xsvf_buffer;
 
+void cpld_jtag_init(jtag_t* const jtag) {
+	/* Initialize pin GPIOs in "released" state. */
+	cpld_jtag_release(jtag);
+
+	/* TDI and TMS pull-ups are required in all JTAG-compliant devices.
+	 *
+	 * The HackRF CPLD is always present, so let the CPLD pull up its TDI and TMS.
+	 *
+	 * The PortaPack may not be present, so pull up the PortaPack TMS pin from the
+	 * microcontroller.
+	 *
+	 * TCK is recommended to be held low, so use microcontroller pull-down.
+	 *
+	 * TDO is undriven except when in Shift-IR or Shift-DR phases.
+	 * Use the microcontroller to pull down to keep from floating.
+	 *
+	 * LPC43xx pull-up and pull-down resistors are approximately 53K.
+	 */
+#ifdef USER_INTERFACE_PORTAPACK
+	scu_pinmux(SCU_PINMUX_PP_TMS,   SCU_GPIO_PUP    | SCU_CONF_FUNCTION0);
+	scu_pinmux(SCU_PINMUX_PP_TDO,   SCU_GPIO_PDN    | SCU_CONF_FUNCTION0);
+#endif
+	scu_pinmux(SCU_PINMUX_CPLD_TMS, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
+	scu_pinmux(SCU_PINMUX_CPLD_TDI, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
+	scu_pinmux(SCU_PINMUX_CPLD_TDO, SCU_GPIO_PDN    | SCU_CONF_FUNCTION4);
+	scu_pinmux(SCU_PINMUX_CPLD_TCK, SCU_GPIO_PDN    | SCU_CONF_FUNCTION0);
+}
+
+void cpld_jtag_take(jtag_t* const jtag) {
+	const jtag_gpio_t* const gpio = jtag->gpio;
+
+#ifdef USER_INTERFACE_PORTAPACK
+	/* Do not drive PortaPack-specific TMS pin initially, just to be cautious. */
+	gpio_input(gpio->gpio_pp_tms);
+	gpio_input(gpio->gpio_pp_tdo);
+#endif
+	gpio_output(gpio->gpio_tms);
+	gpio_output(gpio->gpio_tdi);
+	gpio_output(gpio->gpio_tck);
+	gpio_input(gpio->gpio_tdo);
+}
+
+void cpld_jtag_release(jtag_t* const jtag) {
+	const jtag_gpio_t* const gpio = jtag->gpio;
+
+	/* Make all pins inputs when JTAG interface not active.
+	 * Let the pull-ups/downs do the work.
+	 */
+#ifdef USER_INTERFACE_PORTAPACK
+	/* Do not drive PortaPack-specific pins, initially, just to be cautious. */
+	gpio_input(gpio->gpio_pp_tms);
+	gpio_input(gpio->gpio_pp_tdo);
+#endif
+	gpio_input(gpio->gpio_tms);
+	gpio_input(gpio->gpio_tdi);
+	gpio_input(gpio->gpio_tck);
+	gpio_input(gpio->gpio_tdo);
+
+	/* Set initial GPIO state to the voltages of the internal or external pull-ups/downs,
+	 * to avoid any glitches.
+	 */
+#ifdef USER_INTERFACE_PORTAPACK
+	gpio_set(gpio->gpio_pp_tms);
+#endif
+	gpio_set(gpio->gpio_tms);
+	gpio_set(gpio->gpio_tdi);
+	gpio_clear(gpio->gpio_tck);
+}
+
 /* return 0 if success else return error code see xsvfExecute() */
 int cpld_jtag_program(
 		jtag_t* const jtag,
@@ -37,10 +106,12 @@ int cpld_jtag_program(
         refill_buffer_cb refill
 ) {
 	int error;
+	cpld_jtag_take(jtag);
 	xsvf_buffer = buffer;
 	xsvf_buffer_len = buffer_length;
         refill_buffer = refill;
 	error = xsvfExecute(jtag->gpio);
+	cpld_jtag_release(jtag);
 	
 	return error;
 }

firmware/common/cpld_jtag.h

@@ -43,6 +43,10 @@ typedef struct jtag_t {
 
 typedef void (*refill_buffer_cb)(void);
 
+void cpld_jtag_init(jtag_t* const jtag);
+void cpld_jtag_take(jtag_t* const jtag);
+void cpld_jtag_release(jtag_t* const jtag);
+
 /* Return 0 if success else return error code see xsvfExecute() see micro.h.
  *
  * We expect the buffer to be initially full of data. After the entire

firmware/common/hackrf_core.c

@@ -33,6 +33,7 @@
 #include "w25q80bv_target.h"
 #include "i2c_bus.h"
 #include "i2c_lpc.h"
+#include "cpld_jtag.h"
 #include <libopencm3/lpc43xx/cgu.h>
 #include <libopencm3/lpc43xx/ccu.h>
 #include <libopencm3/lpc43xx/scu.h>
@@ -758,49 +759,11 @@ void ssp1_set_mode_max5864(void)
 	spi_bus_start(max5864.bus, &ssp_config_max5864);
 }
 
-static void jtag_setup(void) {
-	/* TDI and TMS pull-ups are required in all JTAG-compliant devices.
-	 * Therefore, do not pull up TDI and TMS on HackRF CPLD, which is always present.
-	 * HackRF TMS and TDI are dedicated, just drive instead of pulling up/down.
-	 * TCK is recommended to be held low.
-	 * TDO is undriven except when in Shift-IR or Shift-DR phases, so pull down to keep from floating.
-	 * Nail down other signals before causing any transitions on TCK, to prevent undesired
-	 * state changes.
-	 */
-	/* LPC43xx pull-up and pull-down resistors are approximately 53K. */
-#ifdef USER_INTERFACE_PORTAPACK
-	gpio_set(jtag_gpio_cpld.gpio_pp_tms);
-#endif
-	gpio_set(jtag_gpio_cpld.gpio_tms);
-	gpio_set(jtag_gpio_cpld.gpio_tdi);
-	gpio_clear(jtag_gpio_cpld.gpio_tck);
-
-#ifdef USER_INTERFACE_PORTAPACK
-	/* Do not drive PortaPack-specific pins, initially, just to be cautious. */
-	gpio_input(jtag_gpio_cpld.gpio_pp_tms);
-	gpio_input(jtag_gpio_cpld.gpio_pp_tdo);
-#endif
-	gpio_output(jtag_gpio_cpld.gpio_tms);
-	gpio_output(jtag_gpio_cpld.gpio_tdi);
-	gpio_output(jtag_gpio_cpld.gpio_tck);
-	gpio_input(jtag_gpio_cpld.gpio_tdo);
-
-	/* Configure CPLD JTAG pins */
-#ifdef USER_INTERFACE_PORTAPACK
-	scu_pinmux(SCU_PINMUX_PP_TMS,   SCU_GPIO_PUP    | SCU_CONF_FUNCTION0);
-	scu_pinmux(SCU_PINMUX_PP_TDO,   SCU_GPIO_PDN    | SCU_CONF_FUNCTION0);
-#endif
-	scu_pinmux(SCU_PINMUX_CPLD_TMS, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
-	scu_pinmux(SCU_PINMUX_CPLD_TDI, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
-	scu_pinmux(SCU_PINMUX_CPLD_TDO, SCU_GPIO_PDN    | SCU_CONF_FUNCTION4);
-	scu_pinmux(SCU_PINMUX_CPLD_TCK, SCU_GPIO_NOPULL | SCU_CONF_FUNCTION0);
-}
-
 void pin_setup(void) {
 	/* Configure all GPIO as Input (safe state) */
 	gpio_init();
 
-	jtag_setup();
+	cpld_jtag_init(&jtag_cpld);
 
 	/* Configure SCU Pin Mux as GPIO */
 	scu_pinmux(SCU_PINMUX_LED1, SCU_GPIO_NOPULL);

firmware/common/ui_portapack.c

@@ -503,6 +503,11 @@ static uint32_t jtag_pp_shift(const uint32_t tms_bits, const size_t count) {
 }
 
 static uint32_t jtag_pp_idcode() {
+	cpld_jtag_take(&jtag_cpld);
+
+	/* TODO: Check if PortaPack TMS is floating or driven by an external device. */
+	gpio_output(jtag_cpld.gpio->gpio_pp_tms);
+
 	/* Test-Logic/Reset -> Run-Test/Idle -> Select-DR/Scan -> Capture-DR */
 	jtag_pp_shift(0b11111010, 8);
 
@@ -512,6 +517,8 @@ static uint32_t jtag_pp_idcode() {
 	/* Exit1-DR -> Update-DR -> Run-Test/Idle -> ... -> Test-Logic/Reset */
 	jtag_pp_shift(0b11011111, 8);
 
+	cpld_jtag_release(&jtag_cpld);
+
 	return idcode;
 }
 
@@ -998,9 +1005,6 @@ static const hackrf_ui_t portapack_ui = {
 };
 
 const hackrf_ui_t* portapack_detect(void) {
-	/* TODO: Check if PortaPack TMS is floating or driven by an external device. */
-	gpio_output(jtag_cpld.gpio->gpio_pp_tms);
-
 	if( jtag_pp_idcode() == 0x020A50DD ) {
 		return &portapack_ui;
 	} else {