
Chapter 10. General Programmable Interface (GPIF) Page 10-11
10.3 Programming the GPIF Waveforms
Each GPIF Waveform Descriptor can define up to 7 States. In each State, the GPIF can be pro-
grammed to:
• Drive (high or low) or float the CTL outputs
• Sample or drive the FIFO Data bus
• Increment the value on the GPIF Address bus
• Increment the pointer into the current FIFO
• Trigger a GPIFWF (GPIF Waveform) interrupt
Additionally, each State may either sample any two of the following:
• The RDYx input pins
• A FIFO flag
• The INTRDY (internal RDY) flag
• The Transaction-Count-Expired flag
then AND, OR, or XOR the two terms and branch on the result to any State
or:
• Delay a specified number [1-256] of IFCLK cycles
States which sample and branch are called “Decision Points” (DPs); States which don’t are called
“Non-Decision Points” (NDPs).
Figure 10-6. GPIF State Machine Overview
trig
(up to 7 programmable states)
and
GPIF State Machine
INTRDY bit
GPIFWF ISR
Event
Firmware Hooks
State X
State Y
NDP DP
State 7
State 7
IDLE
IDLE
CPU
Y
where:
1
6
(reserved)
CPU GPIF
X = Y-1
(A
LFunc
B)
{
AND,
OR,
XOR
}
Done
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