
Mouse
3.3.9.1Packet Format 1
When there is only X, Y delta data, the transmitted packet is two bytes.
Table | Packet Format 1 | |
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|
|
Byte 1 |
| Byte 2 |
X Delta |
| Y Delta |
(8 bits) |
| (8 bits) |
3.3.9.2 | Packet Format 2 |
|
| ||
| When there is either | ||||
| case where there is no X, Y delta data, but there is | ||||
| set to zero. The | ||||
| Table | Packet Format 2 |
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| |
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| Byte 1 |
| Byte 2 | Byte 3 |
|
| X Delta |
| Y Delta | Buttons (Bits[7:5]), |
|
| (8 bits) |
| (8 bits) | Z Delta (Bits[4:0]) |
|
3.3.9.3 Packet Format 3
When battery voltage level is communicated, the transmitted packet is 1 byte.
Table
Byte 1
Battery Level (1 – 10)
3.3.10 Interrupt usage and timing
In the RDK mouse, the following interrupts has been enabled:
■Motion interrupt from the optical sensor
■Button (Left, Middle and Right buttons) interrupt
■Bind button interrupt
The interrupt latency includes two portions. The first portion is the time between the assertion of an enabled interrupt and the start of its ISR, which can be calculated using the following equation:
Latency1 = Time for current instruction to finish +
Time for M8C to change program counter to interrupt address + Time for LJMP instruction in interrupt table to execute.
For example, if the
(1 to 5 cycles for JMP to finish) + (13 cycles for interrupt routine) +
(7 cycles for LJMP) = 21 to 25 cycles.
In the example above, at 12 MHz, 25 clock cycles take 2.083 µs.
48 | CY4672 Reference Design Guide, Document # |
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