OpenNuvoton N76E003-BSP adopted for Small Device C Compiler (SDCC) with some defines to make Visual Studio Code happy
BSP itself compressed into a couple of bsp/N76E003.h and bsp/N76E003.c files with multiple auxiliary APIs/drivers located in the bsp and lib folders.
BSP requires SDCC version 4.2 and up (tested with SDCC versions 4.2.0 and 4.5.0).
Repository structure:
├── .vscode : some Visual Code settings and common tasks
│ └── tasks.json: defines the following tasks:
│ ├── build: build in the current folder
│ ├── clean: make clean in the current folder
│ ├── re-build: make clean; make; in the current folder
│ ├── erase device: erase all memory types and configuration bytes
│ └── flash device: flash the image from the current folder
├── bsp : common system files
│ ├── N76E003.c/h: main definitions for N76E003
│ ├── adc.c/h: ADC APIs
│ ├── event.c/h: simple ring buffer for generating events from ISRs
│ ├── i2c.c/h: I2C bus APIs
│ ├── iap*.c/h: In Application Programming routines to read/write MCU flash memory
│ ├── irq.c/h: interrupts handling APIs
│ ├── key.c/h: simple driver for keys (push buttons) connected to pull-up pins
│ ├── key.svg: diagram of keys handling and events generation
│ ├── pinterrupt.c/h: pin interrupt handling APIs
│ ├── pwm.c/h: PWM handling APIs
│ ├── terminal.c/h: serial communication APIs enough to support simple CLI with one line history
│ ├── tick.c/h: wake-up timer (WKT) interrupt to provide milliseconds tick events
│ ├── uart.c/h: UART 0/1 APIs.
│ └── vdd.c: ADC bandgap for calculating Vdd value
├── lib : library of common drivers
│ ├── bv4618.c/h: BV4618 LCD controller driver
│ ├── dht.c/h: DHT/AM2302 relative humidity/temperature driver
│ ├── ds3231.c/h: DS3231 Real Time Clock driver
│ ├── dump.c/h: simple pretty printer for memory dumps
│ ├── ht1621.c/h: Holtek HT1621 RAM Mapping 32x4 LCD Controller driver
│ ├── i2c_mem.c/h: I2C EEPROM 24C* driver
│ ├── lcd_lpwm.c/h: driver for LCD used to XY-LPWM and clone boards
│ ├── pcf8574.c/h: I2C I/O Extender PCF8574 driver
│ ├── pwm_range.c/h: helper functions to specify PWM frequency ranges
│ └── srfs.c: read any SFR register by its address
├── pys : python scripts
│ └── size-mcs51.py: .mem file parser for mcs51 target generated by sdcc linker
├── xsamples
│ ├── bsp-pwm: testing PWM capabilities of N76E003
│ ├── bsp-pwm-asymmetric: PWM signals generated by PWM interrupt handler
│ ├── bsp-spi: test different SPI configuration options
│ ├── bsp-template: template project for the BSP
│ ├── bsp-test: testing environment for bsp/lib
│ ├── hpdl-1414: HPDL-1414 Alphanumeric display example
│ ├── pwm-low-power: PWM to drive LED depending on Li-ion battery voltage,
│ │ power-down mode example
│ ├── xy-lpwm-fw: alternative firmware for XY-LPWM and clones
│ └── xy-lpwm-lcd: XY-LPWM LCD screen controlled by commands over serial port
└── readme.md: this file
bsp-pwm provides examples of PWM configurations and PWM interrupt processing, including phased PWM implemented using SW interrupt processing.
bsp-pwm-asymmetric provides examples of PWM signals generated by PWM interrupt processing, including inphase and antiphase signals.
bsp-spi test some of SPI configuration options and use of SPSR::TXBUF flag.
bsp-template provides skeleton example for the BSP.
bsp-test provides examples of connecting different sensors/devices to N76E003 development board:
- DHT22 (AM2302) humidity/temperature sensor
- RTC DS3231 with I2C EEPROM Atmel 24C32 on board
- 20x4 LCD with BV4618 as I2C controller
- 16x4 LCD with PCF8574 as I2C controller
- PS/2 Mini Keyboard UK Layout
- HT16K33 based quad alphanumeric display
hpdl-1414 HPDL-1414 Alphanumeric display controlled using MCP23017 I2C 16-Bit I/O Expander xy-lpwm-fw and xy-lpwm-lcd examples use popular XY-LPWM single channel PWM generator as a development board for N76E003.
XY-LPWM3 with 3 PWM channels would be even better dev board as it provides 8 keys instead or 4 and 3 PWM outputs instead of 1, example with XY-LPWM3 TDB.
BSP implements a simple Even Driven Architecture (EDA) where events are generated by interrupts procedures and then processed in the main loop. By default two interrupts are handled and generates events: UART and Timer:
...
/**
* generate EVT_TIMER every 250 msec, 4 times per second
* set to 253 instead of 250 in case if 16.6MHz is used as Fsys
* */
tick_init(250);
EA = 1; /* enable all interrupts to start tick timer */
...
/* events processing loop */
while (1) {
evt.evt = event_get();
if (evt.type) {
if (evt.type == EVT_UART_RX) {
cli_interact(evt.data);
continue;
}
if (evt.type == EVT_TICK) {
tick++;
/**
* we have 4 tick events per second, so
* count to 4 before calling our timer handler
* */
if (tick >= 4) {
timer();
tick = 0;
}
continue;
}
}
}See event.h and event.c for more details.
To compile any of the examples make sure that you have make (make from avr-gcc works just fine), sdcc and Nuvoton's ICP nulink in the path. If not, modify corresponding defines in the makefiles.
You also will need Python 3.x installed for size-mcs51.py to work.
This script parses .mem file generated by SDCC linker and list information about memory sections:
> size-mcs51.py main.mem
Name Start End Size Max Spare
---------------- ------ ------ ----- ----- -----------
REG BANKS 0x0000 0x000F 2 4 2
IDATA 0x0000 0x008B 140 256 116
OVERLAYS 3
STACK 0x008C 0x00FF 116 248 116
EXTERNAL RAM 0x0001 0x00e6 230 768 538 70.1% free
ROM/EPROM/FLASH 0x0000 0x36b7 14008 18432 4424 24.0% free
Visual Studio Code IntelliSence configuration expects SDCCPATH environment variable to point to SDCC installation folder (needed to access SDCC header files).
There are a few different Nuvoton N76E003 development boards available online.
This one was used for the BSP examples:
Minimal configuration uses programmer pins and UART (38400 baud rate):
G R C D V + 3 T R G
N S L A D 5 V X X N
D T K T D V 3 0 0 D
| | | | | | | | | |
+----------------------+
---|11 P1.4 VDD 9 |--- VDD
---|12 P1.3 GND 7 |--- GND
---|13 P1.2 P1.5 10|---
---|14 P1.1 P1.6 8 |--- DAT [ICP]
---|15 P1.0 P1.7 7 |---
---|16 P0.0 P3.0 5 |---
---|17 P0.1 P2.0 2 |--- RST [ICP]
[ICP] CLK ---|18 P0.2 P0.7 3 |--- UART0 RX
---|19 P0.3 P0.6 2 |--- UART0 TX
---|20 P0.4 P0.5 1 |---
+----------------------+
leaving 13 IO pins available.
This one was used for the pwm-low-power example:
G V R T
N D X X
D D 0 0
| | | |
+---------------------+
---|11 P1.4 P1.5 11|--- (BLINK)
---|12 P1.3 VDD 10|--- VDD
---|13 P1.2 VIN 9 |--- VIN
---|14 P1.1 GND 8 |--- GND
---|15 P1.0 P1.7 7 |---
---|16 P0.0 P3.0 5 |---
---|17 P0.1 P2.0 2 |--- RST [ICP]
[ICP] CLK ---|18 P0.2 P0.7 3 |--- UART0 RX
---|19 P0.3 P0.6 2 |--- UART0 TX
---|20 P0.4 P0.5 1 |---
+---------------------+
| | | | |
G R C D V
N S L A D
D T K T D
Note that this board does not have P1.6 (DAT [ICP]) exposed on the side pins.
Pin P1.5 has on-board blink LED connected.
7133-1 voltage regulator (24V to 3.3V):
M5333B voltage regulator (35V to 3.3V):
Three channel board (not tested used for BSP):
Nuvoton N76E003 official site https://www.nuvoton.com/products/microcontrollers/8bit-8051-mcus/low-pin-count-8051-series/n76e003/
NuMicro software development tools https://github.com/OpenNuvoton/Nuvoton_Tools
OpenNuvoton NuMicro 8051 Family BSP / Sample Code https://github.com/OpenNuvoton/NuMicro-8051-Family
OpenNuvoton N76E003 BSP v2.0 https://github.com/OpenNuvoton/N76E003_BSP
Small Device C Compiler http://sdcc.sourceforge.net/