CHAPTER 3 – Jumper setting
28 SPI-8450-LLVA
I/O addresses and instructions
The table below lists I/O addresses for use as COM2.
I/O address DLAB Read/Write Register
W Transmitter holding Register THR
0R Receiver buffer Register RBR
02F8H 1 W Divisor latch Register (LSB) DLL
1 W Divisor latch Register (MSB) DLM
02F9H 0 W Interrupt enable Register IER
02FAH X R Interrupt ID Register IIR
02FBH X W Line control Register LCR
02FCH X W Modem Control Register MCR
02FDH X R Line status Register LSR
02FEH X R Modem Status Register MSR
02FFH X R/W Scratch Register SCR