1. Keeping the Sheep Corralled An engineer, a physicist, and a mathematician are shown a pasture with a herd of sheep, and told to put them inside the smallest possible amount of fence. The engineer is first. He herds the sheep into a circle and then puts the fence around them, declaring, "A circle will use the least fence for a given area, so this is the best solution. The physicist is next. She creates a circular fence of infinite radius around the sheep, and then draws the fence tight around the herd, declaring, "This will give the smallest circular fence around the herd.

2. Keeping the Sheep Corralled The mathematician is last. After giving the problem a little thought, he puts a small fence around himself and then declares, "I define myself to be on the outside!"

3. Liquid Crystal Display Embedded Systems Interfacing Laboratory Timing, timing, timing …

4. Overview Task 1 – Prelab Task 2 – initPMP & _10usDelay Task 3 – Instruction Sequence and initLCD Task 4 – Application initPMP initLCD cmdLCD putLCD main

5. LCD Interface 8-bit Data Bus 3-bit Control Bus

6. LCD Interface 8-bit Data Bus 3-bit Control Bus

7. LCD Controller (SK0032 1 ) Tianma TM162JCWAG1 16 Cols x 2 Lines SK0032 PIC24FJ128 1 Hitachi HD44780U Compatible Controller/Driver

8. LCD Controller (S6A0069 1 ) Lumex LCD-SO1602 16 Cols x 2 Lines S6A0069 PIC24FJ128 1 Hitachi HD44780U Compatible Controller/Driver

9. Parallel Master Port (PMP) Configure PMCON PMMODE PMADDR PMAEN See Prelab for suggested bit patterns

10. Control Signal R/W – Read/Write Select Signal RS – Register Select 0 = Instruction Register on write and Busy Flag on read 1 = Data Register on read and write E – Enable Signal Check waveforms to make sure your values for WAITB, WAITM, and WAITE meet timing requirements of LCD

11. WAITB, WAITM, and WAITE If WAITM = 0b0000, then WAITB and WAITE have no affect Else WAITM 0b0000, then WAITB, WAITM, and WAITE have an affect WAITM x Tcy (WAITB+1) x Tcy (WAITE+1) x Tcy E Stable

12. Delays – Task 2 – MPLAB SIM msDelay – Already in Peripherals.H Change msDelay scale factor to 333L _10usDelay(unsigned char n){ unsigned char count; for(count=n*usSCALE;count>0;count--){ asm(nop);..... } }

13. Task 2 Hello world Via holes and LCD pins have different signal pin outs. MSO Explorer-16 Check PMP timing against data sheet

14. Instruction Sequence – Task 3

15. Instruction Execution Times Power-On Delay >30 ms (100 ms) Slow Instructions ( > 1.35 ms) Clear display Home cursor Fast Instructions (> 43 us) All other commands and data

16. Functions – Task 3 initLCD – Initialize LCD Main initPMP initLCD Endless loop with Nop( )

17. Warning On Task 4 Task 3 may have confused the LCD controller Turn off power to Explorer-16 board. Turn on power to Explorer-16 board Debugger | Connect Reset Run Reset LCD Controller

18. Functions – Task 4 putLCD – send character to LCD cmdLCD – send new command to LCD Main initPMP and initLCD Endless loop Send message to display using putLCD Home cursor or clear display using cmdLCD