I'm using the LCDB controller on MSP430FG6626 to drive a segment LCD glass. LCD info: www.digikey.com/.../1118603 Configuration: 4-MUX, 3-bias, internal bias generator, V(LCD) is sourced internally as Vcc (no charge pump), no blinking, interrupts disabled, Vcc = 3.3V, debugging using MSPFET. when directly writing into LCD memories (LCDMx), the displayed characters on LCD are not correct. Plus, some segments show lighter contracts than others, and fade away in seconds, although their display states are not changed. Oscilloscope testing shows that only COM0 pin has the correct waveform, but COM1~COM3 pins do not have any rectangular waves. Instead, COM1~COM3 show random spikes with peak voltages ranging from 0.2~1 V, and primary frequencies ranging from 20~100 Hz. (sometimes even negative voltage) So the problem is likely in MCU, not in LCD glass. I tried 2 different devices, both show the same problem. (tried 2-bias too, COM1~COM3 pins not working either) LCD configuration code: LCDBMEMCTL = LCDCLRBM + LCDCLRM; // clear all LCD memory LCDBPCTL0 = 0xFFFF; // select LCD pins LCDBPCTL1 = 0x00FF; LCDBPCTL2 = 0x00FF; LCDBCTL0 = LCDON; // LCD clock source is ACLK (32768Hz), LCDCLK = 455Hz; frame rate = 57Hz, 4 MUX LCDBCTL0 |= LCDDIV__9 + LCDPRE__8 + LCDMX1 + LCDMX0 + LCDSON; LCDBVCTL = 0; // 1/3 bias // then write into LCDM here.... LCD module pin connections: (Pin 22) P2.4/P2MAP4/R03 --- configured as P2.4 (digital input) (Pin 24) P2.6/P2MAP6/LCDREF/R13 --- configured as P2.6, output high (no connection) (Pin 25) P2.7/P2MAP7/R23 --- configured as P2.7 (digital output) (Pin 29) LCDCAP/R33 --- not used (connects to GND) (Pin 30) COM0 --- (connects to COM0 of LCD) (Pin 31) P5.3/COM1/S42 --- configured as COM1 (connects to COM1 of LCD) (Pin 32) P5.4/COM2/S41 --- configured as COM2 (connects to COM2 of LCD) (Pin 33) P5.5/COM3/S40 --- configured as COM3 (connects to COM3 of LCD) Segment pins used: S0~S23, and S32~S39 Any hint what's wrong?
↧