pbio/drv/rproc/rproc_ev3_pru1.h: Share with PRU project

This makes it much easier to keep the projects in sync.

Author: ArcaneNibble

lib/pbio/drv/pwm/pwm_ev3.c

@@ -20,7 +20,7 @@ static pbio_error_t pbdrv_pwm_tiam1808_set_duty(pbdrv_pwm_dev_t *dev, uint32_t c
         return PBIO_SUCCESS;
     }
 
-    pbdrv_rproc_ev3_pru1_shared_ram.pwms[ch] = value;
+    pbdrv_rproc_ev3_pru1_shared_ram.pwm_duty_cycle[ch] = value;
     return PBIO_SUCCESS;
 }
 

lib/pbio/drv/rproc/rproc_ev3.h

@@ -4,18 +4,11 @@
 #ifndef _INTERNAL_PBDRV_RPROC_EV3_H_
 #define _INTERNAL_PBDRV_RPROC_EV3_H_
 
-#include <stdint.h>
-
 // EV3 PRU interfaces and ABI
 // These need to match the interface expected by the PRU firmware
 
 // PRU1 interface
-
-#define PBDRV_RPROC_EV3_PRU1_NUM_PWM_CHANNELS   4
-
-typedef struct {
-    uint8_t pwms[PBDRV_RPROC_EV3_PRU1_NUM_PWM_CHANNELS];
-} pbdrv_rproc_ev3_pru1_shared_ram_t;
+#include "rproc_ev3_pru1.h"
 
 extern volatile pbdrv_rproc_ev3_pru1_shared_ram_t pbdrv_rproc_ev3_pru1_shared_ram;
 

lib/pbio/drv/rproc/rproc_ev3_pru1.h

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2025 The Pybricks Authors
+
+#ifndef _INTERNAL_PBDRV_RPROC_EV3_PRU1_H_
+#define _INTERNAL_PBDRV_RPROC_EV3_PRU1_H_
+
+#include <stdint.h>
+
+// This file is shared between the PRU1 source code
+// and the Pybricks source code. It defines the ABI
+// between the two codebases and must be kept in sync.
+
+#define PBDRV_RPROC_EV3_PRU1_NUM_PWM_CHANNELS   4
+
+typedef struct {
+    union {
+        // u32 used by the PRU codebase to get more-efficient codegen
+        uint32_t pwms;
+        // PWM duty cycle for each channel, range [0-255]
+        uint8_t pwm_duty_cycle[PBDRV_RPROC_EV3_PRU1_NUM_PWM_CHANNELS];
+    };
+} pbdrv_rproc_ev3_pru1_shared_ram_t;
+
+#endif // _INTERNAL_PBDRV_RPROC_EV3_PRU1_H_