668-0011 Rabbit Semiconductor, 668-0011 Datasheet - Page 190

• Manufacturer Part Number: 668-0011
• Description: IC MPU RABIT3000A 55.5MHZ128LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 668-0011

• Rohs Status: RoHS non-compliant
• Processor Type: Rabbit 3000 8-Bit
• Speed: 55.5MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Features: -
• Other names: 316-1043

21.2 Dependencies
21.2.1 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.
21.2.2 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.
21.2.3 Other Registers
21.2.4 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.
180
TAT10R
Register
Option 1
Option 2
Inputs
Time constant for Quadrature Decoder clock
PF1
PF5
Channel 1
I
PF0
PF4
Q
Rabbit 3000 Microprocessor User’s Manual
Function
PF3
PF7
Channel 2
I
PF2
PF6
Q