Kaoru Onoe / HT1621

A simple library for Holtek's HT1621 segment LCD driver

HT1621.cpp@0:3001ada71ba5, 2013-12-21 (annotated)

Committer:
kayekss
Date:
Sat Dec 21 13:29:11 2013 +0000
Revision:
0:3001ada71ba5
First release

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kayekss 0:3001ada71ba5 1 #include "mbed.h"
kayekss 0:3001ada71ba5 2 #include "HT1621.h"
kayekss 0:3001ada71ba5 3
kayekss 0:3001ada71ba5 4 HT1621::HT1621(PinName wrPin, PinName dataPin, PinName csPin)
kayekss 0:3001ada71ba5 5 :
kayekss 0:3001ada71ba5 6 wr(wrPin),
kayekss 0:3001ada71ba5 7 data(dataPin),
kayekss 0:3001ada71ba5 8 cs(csPin)
kayekss 0:3001ada71ba5 9 {
kayekss 0:3001ada71ba5 10 wr = 1;
kayekss 0:3001ada71ba5 11 cs = 1;
kayekss 0:3001ada71ba5 12
kayekss 0:3001ada71ba5 13 command(SYS_DIS);
kayekss 0:3001ada71ba5 14 wait(0.2);
kayekss 0:3001ada71ba5 15 command(SYS_EN);
kayekss 0:3001ada71ba5 16 command(RC_256K);
kayekss 0:3001ada71ba5 17 command(LCD_OFF);
kayekss 0:3001ada71ba5 18
kayekss 0:3001ada71ba5 19 // Clear all segments
kayekss 0:3001ada71ba5 20 for (uint8_t i = 0; i < 64; i++) {
kayekss 0:3001ada71ba5 21 write(i, 0x00);
kayekss 0:3001ada71ba5 22 }
kayekss 0:3001ada71ba5 23 command(LCD_ON);
kayekss 0:3001ada71ba5 24 }
kayekss 0:3001ada71ba5 25
kayekss 0:3001ada71ba5 26 HT1621::~HT1621() {
kayekss 0:3001ada71ba5 27 }
kayekss 0:3001ada71ba5 28
kayekss 0:3001ada71ba5 29 void HT1621::command(uint8_t b) {
kayekss 0:3001ada71ba5 30 // 11 10 9 8| 7 6 5 4| 3 2 1 0
kayekss 0:3001ada71ba5 31 // --------+--+-----------+-----------
kayekss 0:3001ada71ba5 32 // 1 0 0| command<8:0>
kayekss 0:3001ada71ba5 33 uint16_t word = 0x0800 | (b << 1);
kayekss 0:3001ada71ba5 34
kayekss 0:3001ada71ba5 35 cs = 0;
kayekss 0:3001ada71ba5 36 for (uint8_t i = 11; i <= 11; i--) {
kayekss 0:3001ada71ba5 37 wr = 0;
kayekss 0:3001ada71ba5 38 data = word & (0x0001 << i) ? 1 : 0;
kayekss 0:3001ada71ba5 39 wr = 1;
kayekss 0:3001ada71ba5 40 }
kayekss 0:3001ada71ba5 41 cs = 1;
kayekss 0:3001ada71ba5 42 }
kayekss 0:3001ada71ba5 43
kayekss 0:3001ada71ba5 44 void HT1621::write(uint8_t addr, uint8_t b) {
kayekss 0:3001ada71ba5 45 // 12|11 10 9 8| 7 6 5 4| 3 2 1 0
kayekss 0:3001ada71ba5 46 // --+-----+-----+-----------+-----------
kayekss 0:3001ada71ba5 47 // 1 0 1| address<5:0>| seg<3:0>
kayekss 0:3001ada71ba5 48 uint16_t word = 0x1400 | ((addr & 0x3f) << 4) | (b & 0x0f);
kayekss 0:3001ada71ba5 49
kayekss 0:3001ada71ba5 50 cs = 0;
kayekss 0:3001ada71ba5 51 for (uint8_t i = 12; i <= 12; i--) {
kayekss 0:3001ada71ba5 52 wr = 0;
kayekss 0:3001ada71ba5 53 data = word & (0x0001 << i) ? 1 : 0;
kayekss 0:3001ada71ba5 54 wr = 1;
kayekss 0:3001ada71ba5 55 }
kayekss 0:3001ada71ba5 56 cs = 1;
kayekss 0:3001ada71ba5 57 }