Serial LCD display for PIC projects ?

[zorgloub]

Here is the simple code:

' ************************************************** ************************
' Programme: Test SEROUT.PBP
' RGL 02-2022
' Testing AXE134 (Picaxe 4x20# OLED Display) ---> PIC 16F630
' PicBasicPro Compiler V:2.40
' ************************************************** ************************


Include "modedefs.bas"

' Pic Specifications
'--------------------
'PIC16F630 with 16Mhz resonator
@ Device Pic16F630,HS_OSC, WDT_OFF, PWRT_ON, PROTECT_OFF, MCLR_OFF
CMCON = 7 'Deactive Comparator RA0+, RA1-, RA2 out
DEFINE OSC 16
DEFINE CHAR_PACING 500

' ******* VARIABLES / CONSTANTS **************************
Symbol BAUD = N2400
Symbol OLED = PORTA.0 'pin13

'*** Definition i/o
'All OUTPUT
TRISA = 0
TRISC = 0

Pause 1000

Serout OLED, BAUD,[254,1] : pause 30 ' Clear Display
Serout OLED, BAUD,[254,128] : PAuse 30 ' Line1, Col1

LOOP:
Serout OLED, BAUD, ["UUU"]
Pause 1000
Goto Loop

[HenrikOlsson]

The three pulse bursts are well separated by 0.92msec and the display responds well.
What is the relationship between parameter 500 and the 0.92msec timing?
Why not 500µsec?

Because at 2400 baud ~420us of that 0.92ms is the normal stopbit. Add to that the additional character pacing of 500us.

At 2400 baud you'd also get the same result by specifying two stop-bits.

[zorgloub]

@Henrick
I have drawn the timeline in the case of a transmission of two spaced bytes with the command DEFINE CHAR_PACING 1000.
I can see, however, that in addition to the normal Start bit of 410µs, another delay of 410 µs is added to the Pacing 1000!?

[HenrikOlsson]

No, you're forgetting the stop-bit! You have 1 startbit, 8 databits and 1 stopbit.

In your diagram, from left to right: First you have the start-bit (1), then you have 8 data-bits (11000010), then you have the stop-bit (0) and THEN you have the 1000us CHAR_PACING before the next start-bit.