W83877TF Datasheet, PDF (10/154 Pages) Winbond – I/O chip disk drive adapter

W83877TF
3.2.7 Interrupt Control Register (ICR) (Read/Write)
This 8-bit register allows the five types of controller interrupts to activate the interrupt output signal
separately. The interrupt system can be totally disabled by resetting bits 0 through 3 of the Interrupt
Control Register (ICR). A selected interrupt can be enabled by setting the appropriate bits of this
register to a logical 1.
7 65 4 3 2 1 0
00 00
RBR data ready interrupt enable (ERDRI)
TBR empty interrupt enable (ETBREI)
UART receive status interrupt enable (EUSRI)
Handshake status interrupt enable (EHSRI)
Bit 7-4: These four bits are always logic 0.
Bit 3: EHSRI. Setting this bit to a logical 1 enables the handshake status register interrupt.
Bit 2: EUSRI. Setting this bit to a logical 1 enables the UART status register interrupt.
Bit 1: ETBREI. Setting this bit to a logical 1 enables the TBR empty interrupt.
Bit 0: ERDRI. Setting this bit to a logical 1 enables the RBR data ready interrupt.
3.2.8 Programmable Baud Generator (BLL/BHL) (Read/Write)
Two 8-bit registers, BLL and BHL, compose a programmable baud generator that uses 24 MHz to
generate a 1.8461 MHz frequency and divides it by a divisor from 1 to 2¹⁶-1. The output frequency of
the baud generator is the baud rate multiplied by 16, and this is the base frequency for the transmitter
and receiver. The table below illustrates the use of the baud generator with a frequency of 1.8461
MHz. In high-speed UART mode (refer to CR0C bit7 and CR0C bit6), the programmable baud
generator directly uses 24 MHz and the same divisor as the normal speed divisor. In high-speed
mode, the data transmission rate can be as high as 1.5M bps.
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Publication Release Date: March 1998
Version 0.61