20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 244

• 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

22.2 Dependencies
22.2.1 I/O Pins
Each Quadrature Decoder channel can accept the two encoder inputs from one of three
different locations, as shown in the table below. Each channel can select a different input
option. Note that these pins can be used for other peripherals at the same time as the
Quadrature Decoder peripheral; one example of this use is to use measure pulse width on
the I channels with the input capture peripheral.
22.2.2 Clocks
The 8/10-bit Quadrature Decoder counters are clocked from the output of Timer A10, and
can run at rates from the peripheral clock divided by 2 down to the peripheral clock
divided by 512 by writing the appropriate value to TAT10R. The clock rate must be high
enough that transitions on the inputs are sampled in different clock cycles. In addition,
both the I and Q inputs go through a digital filter that rejects pulses shorter than two clock
periods wide.
22.2.3 Other Registers
22.2.4 Interrupts
Each Quadrature Decoder channel can generate an interrupt whenever the counter incre-
ments from 0x0FF (0x3FF in 10-bit mode) to 0x00 or when the counter decrements from
0x000 to 0x0FF (0x3FF for 10-bit mode). The interrupt request is cleared when QDCSR is
read.
The Quadrature Decoder interrupt vector is in the IIR at offset 0x190. It can be set as
Priority 1, 2, or 3.
The status bits in the QDCSR are set coincident with the interrupt request and are reset
when QDCSR is read.
234
TAT10R
Register
Option 1
Option 2
Option 3
Inputs
Time constant for Quadrature Decoder clock
PD1
PE1
PE5
Channel 1
I
PD0
PE0
PE4
Q
Rabbit 4000 Microprocessor User’s Manual
Function
PD3
PE3
PE7
Channel 2
I
PD2
PE2
PE6
Q