20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 127

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

14.3 Operation
The following steps explain how to set up a Timer B countdown timer.
1. Select perclk/2, perclk/16, or countdown timer A1 in TBCR.
2. Use TBCR to select whether countdown timers B1–B2 operate normally with the
3. Enable Timer B by writing a 1 to bit 0 of TBCSR.
14.3.1 Handling Interrupts
The following steps explain how an interrupt is set up and used.
1. Write the vector to the interrupt service routine to the internal interrupt table.
2. Configure TBCSR to select which match registers will generate an interrupt.
3. Configure TBCR to select the interrupt priority (note that interrupts will be enabled
The interrupt request is cleared by reading from TBCSR.
14.3.2 Example ISR
A sample interrupt handler is shown below.
Chapter 14 Timer B
match registers or whether they use the step registers to calculate match values.
once this value is set; this step should be done last).
timerB_isr::
push af
ioi ld a, (TBCSR)
; handle all interrupts flagged in TBCSR here
; reload match register(s) if necessary
pop af
ipres
ret
; save used registers
; clear the interrupt request and get status
; restore used registers
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