Add MAX7219 SPI display driver library + example and small SPI librar…

…y fixes

examples/spi_max7219/Makefile

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+all : flash
+
+TARGET:=spi_max7219
+
+include ../../ch32v003fun/ch32v003fun.mk
+
+flash : cv_flash
+clean : cv_clean
+
+

examples/spi_max7219/README.md

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+# MAX7219 8 digit 7 segment display demo
+
+This example for the `max7219_spi_driver` and `max7219_spi_driver_extended` library demonstrates controlling a MAX7219 or MAX7221 based display over SPI with basic and advanced text writing, and at least one example of every available display function in some capacity.
+
+---
+
+The MAX7219 and MAX7221 chipsets are used in many 8 character 7 segment and 8x8 single colour dot matrix displays which can be purchased preassembled on eBay and AliExpress very cheaply. The abundance and low cost of these displays makes them a great companion for small projects requiring a display output that is more capable than single LEDs but not as complex as something like an LCD.
+
+---
+
+The example expects you to connect a MAX7219 based 7 segment 8 character display to your CH32V003 like so:
+- `DIN` / `MOSI` to `PC6`
+- `SCLK` to `PC5`
+- `CS` to `PD0`
+
+You can choose which examples will be shown on the display by changing the `spi_max7219.c` file in the marked demo selection section. All examples are enabled by default.
+
+Once running, you'll see one of the many examples being displayed like so:
+![Demo of the MAX7219 based 8 digit 7 segment display connected to a CH32V003 dev board, in operation](demo_pic.jpg)

examples/spi_max7219/funconfig.h

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+#ifndef _FUNCONFIG_H
+#define _FUNCONFIG_H
+
+#define CH32V003           1
+
+#endif

examples/spi_max7219/max7219_spi_driver.h

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+/* 
+ * SPI based driver for the MAX7219 display driver (https://www.analog.com/media/en/technical-documentation/data-sheets/MAX7219-MAX7221.pdf)
+ * 
+ * The driver can be used for 64 discrete LED control, or for 8 digits of 7 segment (+ decimal) displays. It includes a basic 7 segment display font called Code B
+ * which is made available with this library, as well as various other functions such as multiplexer scan limiting, digital brightness control and font decoding.
+ * 
+ * The one-byte segment arrangement in the digit registers appear like so:
+ * 
+ *     A
+ *    ---
+ * F | G | B
+ *    --- 
+ * E |   | C
+ *    --- 
+ *     D   . DP
+ * 
+ * +-----+----+----+----+----+----+----+----+----+
+ * | Bit | B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 |
+ * +-----+----+----+----+----+----+----+----+----+
+ * | Seg | DP |  A |  B |  C |  D |  E |  F |  G |
+ * +-----+----+----+----+----+----+----+----+----+
+ * 
+ * On standard 8 digit boards, the 0th digit (MAX7219_REGISTER_DIGIT0) is on the right and the 7th digit (MAX7219_REGISTER_DIGIT7) is on the left.
+ */
+
+//Include guard
+#ifndef MAX7219_SPI_DRIVER_H
+#define MAX7219_SPI_DRIVER_H
+
+//Includes
+#include "ch32v003_SPI.h"
+#include <stdbool.h>
+
+//Instance struct
+struct MAX7219_Display
+{
+    uint8_t displays_in_chain;
+
+    GPIO_TypeDef* chip_select_port;
+    uint8_t chip_select_pin;
+
+    uint8_t last_set_decode_mode;
+};
+
+//Chip select methods
+void MAX7219_select(struct MAX7219_Display display)
+{
+    display.chip_select_port->BSHR |= 0b00000001 << display.chip_select_pin << 16; //Reset pin (active low)
+}
+
+void MAX7219_deselect(struct MAX7219_Display display)
+{
+    display.chip_select_port->BSHR |= 0b00000001 << display.chip_select_pin; //Set pin (active low)
+}
+
+//Raw communication
+#define MAX7219_REGISTER_NOOP 0x00
+/*#define MAX7219_REGISTER_DIGIT0 0x01
+#define MAX7219_REGISTER_DIGIT1 0x02
+#define MAX7219_REGISTER_DIGIT2 0x03
+#define MAX7219_REGISTER_DIGIT3 0x04
+#define MAX7219_REGISTER_DIGIT4 0x05
+#define MAX7219_REGISTER_DIGIT5 0x06
+#define MAX7219_REGISTER_DIGIT6 0x07
+#define MAX7219_REGISTER_DIGIT7 0x08*/
+#define MAX7219_REGISTER_DECODE_MODE 0x09
+#define MAX7219_REGISTER_INTENSITY 0x0A
+#define MAX7219_REGISTER_SCANLIMIT 0x0B
+#define MAX7219_REGISTER_SHUTDOWN 0x0C
+#define MAX7219_REGISTER_DISPLAYTEST 0x0F
+
+void MAX7219_write_register(struct MAX7219_Display display, uint8_t reg, uint8_t data)
+{
+    reg &= 0b00001111; //Remove the top 4 bits as they are not used for the register, and only retain the last 4 bits
+
+    uint16_t packet = reg << 8; //Apply the register address to the final packet in the top 8 bits
+
+    packet |= data; //Apply the data to the final packet in the bottom 8 bits
+
+    MAX7219_select(display); //Select the chip select line
+
+    //Write the packet to the display
+    SPI_begin_16();
+
+    SPI_write_16(packet);
+    SPI_wait_transmit_finished();
+
+    SPI_end();
+
+    MAX7219_deselect(display); //Deselect the chip select line
+}
+
+//Register helpers
+void MAX7219_shutdown(struct MAX7219_Display display, bool set)
+{
+    MAX7219_write_register(display, MAX7219_REGISTER_SHUTDOWN, !set);
+}
+
+void MAX7219_test(struct MAX7219_Display display, bool set)
+{
+    MAX7219_write_register(display, MAX7219_REGISTER_DISPLAYTEST, set);
+}
+
+#define MAX7219_DECODE_MODE_NONE 0x00
+#define MAX7219_DECODE_MODE_0_ONLY 0x01
+#define MAX7219_DECODE_MODE_0_TO_3_ONLY 0x0F
+#define MAX7219_DECODE_MODE_ALL 0xFF
+
+void MAX7219_set_decode_mode(struct MAX7219_Display display, uint8_t mode)
+{
+    MAX7219_write_register(display, MAX7219_REGISTER_DECODE_MODE, mode);
+    display.last_set_decode_mode = mode;
+}
+
+#define MAX7219_SCANLIMIT_0_ONLY 0x00
+#define MAX7219_SCANLIMIT_01 0x01
+#define MAX7219_SCANLIMIT_012 0x02
+#define MAX7219_SCANLIMIT_0123 0x03
+#define MAX7219_SCANLIMIT_01234 0x04
+#define MAX7219_SCANLIMIT_012345 0x05
+#define MAX7219_SCANLIMIT_0123456 0x06
+#define MAX7219_SCANLIMIT_ALL 0x07
+
+void MAX7219_set_scan_limit(struct MAX7219_Display display, uint8_t limit)
+{
+    limit &= 0b00000111; //Only accept the 3 lsbs for this register
+    MAX7219_write_register(display, MAX7219_REGISTER_SCANLIMIT, limit);
+}
+
+#define MAX7219_BRIGHTNESS_MAX 0x0F
+#define MAX7219_MRIGHTNESS_MIN 0x00
+
+void MAX7219_set_brightness(struct MAX7219_Display display, uint8_t brightness)
+{
+    brightness &= 0b00001111; //Only accept the 4 lsbs for this register
+    MAX7219_write_register(display, MAX7219_REGISTER_INTENSITY, brightness);
+}
+
+//Built in CODE B font
+#define MAX7219_CODEB_ADD_DECPOINT 0x80
+#define MAX7219_CODEB_DASH 0x0A
+#define MAX7219_CODEB_BLANK 0x0F
+#define MAX7219_CODEB_0 0x00
+#define MAX7219_CODEB_1 0x01
+#define MAX7219_CODEB_2 0x02
+#define MAX7219_CODEB_3 0x03
+#define MAX7219_CODEB_4 0x04
+#define MAX7219_CODEB_5 0x05
+#define MAX7219_CODEB_6 0x06
+#define MAX7219_CODEB_7 0x07
+#define MAX7219_CODEB_8 0x08
+#define MAX7219_CODEB_9 0x09
+#define MAX7219_CODEB_E 0x0B
+#define MAX7219_CODEB_H 0x0C
+#define MAX7219_CODEB_L 0x0D
+#define MAX7219_CODEB_P 0x0E
+
+//Raw segment
+#define MAX7219_SEGMENT_DP 0b10000000
+#define MAX7219_SEGMENT_A  0b01000000
+#define MAX7219_SEGMENT_B  0b00100000
+#define MAX7219_SEGMENT_C  0b00010000
+#define MAX7219_SEGMENT_D  0b00001000
+#define MAX7219_SEGMENT_E  0b00000100
+#define MAX7219_SEGMENT_F  0b00000010
+#define MAX7219_SEGMENT_G  0b00000001
+
+void MAX7219_set_digit(struct MAX7219_Display display, uint32_t digit, uint8_t value)
+{
+    uint32_t literalDigit = digit % 8;
+    //uint32_t displayIndex = digit / 8;
+
+    MAX7219_write_register(display, literalDigit + 1, value);
+}
+
+void MAX7219_reset(struct MAX7219_Display display)
+{
+    //Set display brightness to maximum
+    MAX7219_set_brightness(display, MAX7219_BRIGHTNESS_MAX);
+
+    //Set the scan limit to all 8 digits enabled
+    MAX7219_set_scan_limit(display, MAX7219_SCANLIMIT_ALL);
+
+    //Enable Code-B decode on all digits
+    MAX7219_set_decode_mode(display, MAX7219_DECODE_MODE_ALL);
+
+    //Clear all digits
+    for (size_t digitPos = 0; digitPos < display.displays_in_chain * 8; digitPos++)
+    {
+        MAX7219_set_digit(display, digitPos, MAX7219_CODEB_BLANK);
+    }
+
+    //Take the display out of shutdown
+    MAX7219_shutdown(display, false);
+
+    //Take the display out of test mode
+    MAX7219_test(display, false);
+}
+
+void MAX7219_init(struct MAX7219_Display display)
+{
+    //Default deselected
+    MAX7219_deselect(display);
+
+    //Ensure port is enabled
+    uint32_t selectedPortAddress = (uint32_t)display.chip_select_port;
+
+    switch (selectedPortAddress)
+    {
+        case GPIOA_BASE:
+            RCC->APB2PCENR |= RCC_APB2Periph_GPIOA;
+            break;
+
+        case GPIOC_BASE:
+            RCC->APB2PCENR |= RCC_APB2Periph_GPIOC;
+            break;
+
+        case GPIOD_BASE:
+            RCC->APB2PCENR |= RCC_APB2Periph_GPIOD;
+            break;
+
+        default: break;
+    }
+
+    //Enable push-pull on pin
+    display.chip_select_port->CFGLR &= ~(0xf<<(4*display.chip_select_pin));
+    display.chip_select_port->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP)<<(4*display.chip_select_pin);
+
+    //Initialise SPI
+    SPI_init();
+
+    //Clear display to driver defaults
+    MAX7219_reset(display);
+}
+
+#endif //MAX7219_SPI_DRIVER_H include guard

examples/spi_max7219/max7219_spi_driver_extended.h

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+//Include guard
+#ifndef MAX7219_SPI_DRIVER_EXTENDED_H
+#define MAX7219_SPI_DRIVER_EXTENDED_H
+
+//Includes
+#include "max7219_spi_driver.h"
+
+//---Extended Font---
+//Letters
+#define MAX7219_EXTFONT_A MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_B MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_C MAX7219_SEGMENT_A | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_C_LOWER MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_D MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_E MAX7219_SEGMENT_A | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_F MAX7219_SEGMENT_A | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_H MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_H_LOWER MAX7219_SEGMENT_C | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_I MAX7219_SEGMENT_E | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_I_LOWER MAX7219_SEGMENT_E
+#define MAX7219_EXTFONT_L MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_L_LOWER MAX7219_SEGMENT_E | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_N MAX7219_SEGMENT_C | MAX7219_SEGMENT_E | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_O MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_O_LOWER MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_P MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_S MAX7219_SEGMENT_A | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_T MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_U MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_U_LOWER MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E
+#define MAX7219_EXTFONT_X MAX7219_SEGMENT_C | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_Y MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_Z MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_G
+
+//Numbers
+#define MAX7219_EXTFONT_0 MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F
+#define MAX7219_EXTFONT_1 MAX7219_SEGMENT_B | MAX7219_SEGMENT_C
+#define MAX7219_EXTFONT_2 MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_3 MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_4 MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_5 MAX7219_SEGMENT_A | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_6 MAX7219_SEGMENT_A | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_7 MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_C
+#define MAX7219_EXTFONT_8 MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_E | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_9 MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_C | MAX7219_SEGMENT_D | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+
+//Symbols
+#define MAX7219_EXTFONT_BLANK 0x00
+#define MAX7219_EXTFONT_DEGREES MAX7219_SEGMENT_A | MAX7219_SEGMENT_B | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_EQUALS_TOP MAX7219_SEGMENT_A | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_EQUALS_BOTTOM MAX7219_SEGMENT_D | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_TRIEQUALS MAX7219_SEGMENT_A | MAX7219_SEGMENT_D | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_HYPHEN MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_UNDERSCORE MAX7219_SEGMENT_D
+#define MAX7219_EXTFONT_OVERSCORE MAX7219_SEGMENT_A
+#define MAX7219_EXTFONT_FORWARDSLASH MAX7219_SEGMENT_B | MAX7219_SEGMENT_E | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_BACKSLASH MAX7219_SEGMENT_C | MAX7219_SEGMENT_F | MAX7219_SEGMENT_G
+#define MAX7219_EXTFONT_DECIMAL MAX7219_SEGMENT_DP
+
+#endif //MAX7219_SPI_DRIVER_EXTENDED_H include guard