LAPIS Semiconductor ML610421, User Manual, Page: 213 / 437

ML610Q421/ML610Q422/ML610421 User’s Manual
Chapter 14 UART
14 – 18
14.4 Specifying port registers
When you want to make sure the UART function is working, please check related port registers are specified. See
Chapter 21, “Port 4” and Chapter 18, “Port 0” for detail about the port registers.
14.4.1 Functioning P43(TXD0) and P42(RXD0) as the UART.
Set P43MD1-P42MD1 bits(bit3-bit2 of P4MOD1 register) to “0” and set P43MD0-P42MD0(bit3-bit2 of P4MOD0
register) to “1”, for specifying the UART as the secondary function of P43 and P42.
Reg. name P4MOD1 register (Address: 0F225H)
Bit 7 6 5 4 3 2 1 0
Bit name
P47MD1 P46MD1 P45MD1 P44MD1 P43MD1 P42MD1 P41MD1 P40MD1
Data * * * * 0 0 * *
Reg. name P4MOD0 register (Address: 0F224H)
Bit 7 6 5 4 3 2 1 0
Bit name
P47MD0 P46MD0 P45MD0 P44MD0 P43MD0 P42MD0 P41MD0 P40MD0
Data * * * * 1 1 * *
Set P43C1 bit(bit3 of P4CON1 register) to “1”, set P43C0 bit(bit3 of P4CON0 register) to “1”, and set P43DIR
bit(bit3 of P4DIR register) to “0”, for specifying the P43 as CMOS output.
Set P42DIR bit(bit2 of P4DIR register) to “1” for specifying the P42 as an input pin.
Data setting to P42C1 bit and P42C0 bit, depend on the application circuit connected to P42.
Reg. name P4CON1 register (Address: 0F223H)
Bit 7 6 5 4 3 2 1 0
Bit name
P47C1 P46C1 P45C1 P44C1 P43C1 P42C1 P41C1 P40C1
Data * * * * 1 $ * *
Reg. name P4CON0 register (Address: 0F222H)
Bit 7 6 5 4 3 2 1 0
Bit name
P47C0 P46C0 P45C0 P44C0 P43C0 P42C0 P41C0 P40C0
Data * * * * 1 $ * *
Reg. name P4DIR register (Address: 0F221H)
Bit 7 6 5 4 3 2 1 0
Bit name
P47DIR P46DIR P45DIR P44DIR P43DIR P42DIR P41DIR P40DIR
Data * * * * 0 1 * *
Data of P43D-P42D bits (bit3-2 of P4D register) do not affect to the UART function, so don’t care the data for the
function.
Reg. name P4D register (Address: 0F220H)
Bit 7 6 5 4 3 2 1 0
Bit name
P47D P46D P45D P44D P43D P42D P41D P40D
Data * * * * ** ** * *
* : Bit not related to the UART(using P43 and P42) function
** : Don’t care the data
$ : Arbitrarily