Hi,
I’m having trouble interpreting the data sheet for the LC7981 controller that’s onboard my CFGA240128-FMI-T LCD. Reading the written description of how to write to the various registers, I’m not seeing any references to the enable pin. The timing diagram, however, appears to show the enable pin as part of the read and write cycles. Here’s a partial example of what I’m doing to try and get the LCD to simply show “ABCDEF” at the top line of the display:
LCD Connections
1 – gnd
2 – 5V
3 – N/C
4 – uController Output Pin
5 – Tied to gnd
6 to 14 – uController Output Pins
15 – Tied to gnd
16 – Tied to 5V
17 to 20 – N/C
Command Sequence 1 (Mode Control)
Set RS
Set Enable
Put 00000000 on Data Bus
Clear Enable
Clear RS
Set Enable
Put 00110000 on Data Bus
Clear Enable
Command Sequence 2 (Character Pitch)
Set RS
Set Enable
Put 00000001 on Data Bus
Clear Enable
Clear RS
Set Enable
Put 00100101 on Data Bus
Clear Enable
Am I on the right track? All I’m getting at this point is a whole screen of jumbled character fragments.
Also, is it best to set the duty to 1/64 or 1/128? The data sheet specifies duty as 1/128 but also says “please set to 1/64”.
Thanks!
I’m having trouble interpreting the data sheet for the LC7981 controller that’s onboard my CFGA240128-FMI-T LCD. Reading the written description of how to write to the various registers, I’m not seeing any references to the enable pin. The timing diagram, however, appears to show the enable pin as part of the read and write cycles. Here’s a partial example of what I’m doing to try and get the LCD to simply show “ABCDEF” at the top line of the display:
LCD Connections
1 – gnd
2 – 5V
3 – N/C
4 – uController Output Pin
5 – Tied to gnd
6 to 14 – uController Output Pins
15 – Tied to gnd
16 – Tied to 5V
17 to 20 – N/C
Command Sequence 1 (Mode Control)
Set RS
Set Enable
Put 00000000 on Data Bus
Clear Enable
Clear RS
Set Enable
Put 00110000 on Data Bus
Clear Enable
Command Sequence 2 (Character Pitch)
Set RS
Set Enable
Put 00000001 on Data Bus
Clear Enable
Clear RS
Set Enable
Put 00100101 on Data Bus
Clear Enable
Am I on the right track? All I’m getting at this point is a whole screen of jumbled character fragments.
Also, is it best to set the duty to 1/64 or 1/128? The data sheet specifies duty as 1/128 but also says “please set to 1/64”.
Thanks!
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