Add mtm_hardware.DACOut audio output for the MTM Workshop Computer

locale/circuitpython.pot

@@ -625,6 +625,7 @@ msgstr ""
 
 #: ports/raspberrypi/common-hal/audiobusio/I2SOut.c
 #: ports/raspberrypi/common-hal/audiopwmio/PWMAudioOut.c
+#: ports/raspberrypi/common-hal/mcp4822/MCP4822.c
 msgid "Audio source error"
 msgstr ""
 
@@ -1300,6 +1301,7 @@ msgstr ""
 msgid "Invalid %q"
 msgstr ""
 
+#: ports/raspberrypi/common-hal/mcp4822/MCP4822.c
 #: ports/raspberrypi/common-hal/picodvi/Framebuffer_RP2350.c
 #: shared-module/aurora_epaper/aurora_framebuffer.c
 msgid "Invalid %q and %q"
@@ -1537,6 +1539,7 @@ msgstr ""
 #: ports/atmel-samd/common-hal/audioio/AudioOut.c
 #: ports/raspberrypi/common-hal/audiobusio/I2SOut.c
 #: ports/raspberrypi/common-hal/audiopwmio/PWMAudioOut.c
+#: ports/raspberrypi/common-hal/mcp4822/MCP4822.c
 msgid "No DMA channel found"
 msgstr ""
 
@@ -1651,7 +1654,7 @@ msgid "Not connected"
 msgstr ""
 
 #: shared-bindings/audiobusio/I2SOut.c shared-bindings/audioio/AudioOut.c
-#: shared-bindings/audiopwmio/PWMAudioOut.c
+#: shared-bindings/audiopwmio/PWMAudioOut.c shared-bindings/mcp4822/MCP4822.c
 msgid "Not playing"
 msgstr ""
 
@@ -2168,6 +2171,7 @@ msgid "Too many channels in sample"
 msgstr ""
 
 #: ports/raspberrypi/common-hal/audiobusio/I2SOut.c
+#: ports/raspberrypi/common-hal/mcp4822/MCP4822.c
 msgid "Too many channels in sample."
 msgstr ""
 
@@ -2266,6 +2270,7 @@ msgstr ""
 #: ports/atmel-samd/common-hal/audioio/AudioOut.c
 #: ports/raspberrypi/common-hal/audiobusio/I2SOut.c
 #: ports/raspberrypi/common-hal/audiopwmio/PWMAudioOut.c
+#: ports/raspberrypi/common-hal/mcp4822/MCP4822.c
 msgid "Unable to allocate buffers for signed conversion"
 msgstr ""
 

ports/raspberrypi/boards/mtm_computer/board.c

@@ -5,5 +5,36 @@
 // SPDX-License-Identifier: MIT
 
 #include "supervisor/board.h"
+#include "shared-bindings/mcp4822/MCP4822.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "peripherals/pins.h"
+#include "py/runtime.h"
 
+// board.DAC() — factory function that constructs an mcp4822.MCP4822 with
+// the MTM Workshop Computer's DAC pins (GP18=SCK, GP19=SDI, GP21=CS).
+
+static mp_obj_t board_dac_singleton = MP_OBJ_NULL;
+
+static mp_obj_t board_dac_factory(void) {
+    if (board_dac_singleton == MP_OBJ_NULL) {
+        mcp4822_mcp4822_obj_t *dac = mp_obj_malloc_with_finaliser(
+            mcp4822_mcp4822_obj_t, &mcp4822_mcp4822_type);
+        common_hal_mcp4822_mcp4822_construct(
+            dac,
+            &pin_GPIO18,   // clock (SCK)
+            &pin_GPIO19,   // mosi (SDI)
+            &pin_GPIO21,   // cs
+            1);            // gain 1x
+        board_dac_singleton = MP_OBJ_FROM_PTR(dac);
+    }
+    return board_dac_singleton;
+}
+MP_DEFINE_CONST_FUN_OBJ_0(board_dac_obj, board_dac_factory);
+
+void board_deinit(void) {
+    if (board_dac_singleton != MP_OBJ_NULL) {
+        common_hal_mcp4822_mcp4822_deinit(MP_OBJ_TO_PTR(board_dac_singleton));
+        board_dac_singleton = MP_OBJ_NULL;
+    }
+}
 // Use the MP_WEAK supervisor/shared/board.c versions of routines not defined here.

ports/raspberrypi/boards/mtm_computer/mpconfigboard.mk

@@ -11,3 +11,4 @@ EXTERNAL_FLASH_DEVICES = "W25Q16JVxQ"
 CIRCUITPY_AUDIOEFFECTS = 1
 CIRCUITPY_IMAGECAPTURE = 0
 CIRCUITPY_PICODVI = 0
+CIRCUITPY_MCP4822 = 1

ports/raspberrypi/boards/mtm_computer/pins.c

@@ -6,6 +6,8 @@
 
 #include "shared-bindings/board/__init__.h"
 
+extern const mp_obj_fun_builtin_fixed_t board_dac_obj;
+
 static const mp_rom_map_elem_t board_module_globals_table[] = {
     CIRCUITPYTHON_BOARD_DICT_STANDARD_ITEMS
 
@@ -21,7 +23,6 @@ static const mp_rom_map_elem_t board_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_PULSE_2_IN), MP_ROM_PTR(&pin_GPIO3) },
     { MP_ROM_QSTR(MP_QSTR_GP3), MP_ROM_PTR(&pin_GPIO3) },
 
-
     { MP_ROM_QSTR(MP_QSTR_NORM_PROBE), MP_ROM_PTR(&pin_GPIO4) },
     { MP_ROM_QSTR(MP_QSTR_GP4), MP_ROM_PTR(&pin_GPIO4) },
 
@@ -105,6 +106,9 @@ static const mp_rom_map_elem_t board_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_A3), MP_ROM_PTR(&pin_GPIO29) },
     { MP_ROM_QSTR(MP_QSTR_GP29), MP_ROM_PTR(&pin_GPIO29) },
 
+    // Factory function: dac = board.DAC() returns a configured mcp4822.MCP4822
+    { MP_ROM_QSTR(MP_QSTR_DAC), MP_ROM_PTR(&board_dac_obj) },
+
     // { MP_ROM_QSTR(MP_QSTR_EEPROM_I2C), MP_ROM_PTR(&board_i2c_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_module_globals_table);