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Z8F0113HJ005EG Datasheet, PDF (123/245 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers
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Z8 Encore! XP® F0823 Series
Product Specification
108
Baud Rate Generator Interrupts
If the Baud Rate Generator (BRG) interrupt enable is set, the UART Receiver interrupt
asserts when the UART Baud Rate Generator reloads. This condition allows the Baud
Rate Generator to function as an additional counter if the UART functionality is not
employed.
UART Baud Rate Generator
The UART Baud Rate Generator creates a lower frequency baud rate clock for data trans-
mission. The input to the Baud Rate Generator is the system clock. The UART Baud Rate
High and Low Byte registers combine to create a 16-bit baud rate divisor value
(BRG[15:0]) that sets the data transmission rate (baud rate) of the UART. The UART data
rate is calculated using the following equation:
UART Data Rate (bits/s) = -1--6-----S---y-U--s--At--e-R-m---T---C-B---l-ao--u-c--kd----FR---r-a-e--tq-e--u--D-e---ni-v--c-i-sy--o--(-r-H--V-z--a-)--l-u---e-
When the UART is disabled, the Baud Rate Generator functions as a basic 16-bit timer
with interrupt on time-out. Observe the following steps to configure the Baud Rate Gener-
ator as a timer with interrupt on time-out:
1. Disable the UART by clearing the REN and TEN bits in the UART Control 0 Register
to 0.
2. Load the acceptable 16-bit count value into the UART Baud Rate High and Low Byte
registers.
3. Enable the Baud Rate Generator timer function and associated interrupt by setting the
BIRQ bit in the UART Control 1 Register to 1.
When configured as a general purpose timer, the interrupt interval is calculated using the
following equation:
Interrupt Interval (s) = System Clock Period (s)  BRG[15:0]
UART Control Register Definitions
The UART control registers support the UART and the associated infrared encoder/decod-
ers. For more information about the infrared operation, see the Infrared Encoder/Decoder
chapter on page 117.
PS024315-1011
PRELIMINARY
UART Control Register Definitions
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