isppac-powr1208 Lattice Semiconductor Corp., isppac-powr1208 Datasheet - Page 16

• Manufacturer Part Number: isppac-powr1208
• Description: In-system Programmable Power Supply Sequencing Controller And Monitor
• Manufacturer: Lattice Semiconductor Corp.

Lattice Semiconductor
16, 32, 64, 128, 256 and 512 (Table 1-3). After the clock for the timers is divided down, it is used to drive the pro-
grammable timers. The four timers share the same timer clock frequency but may have different end count values.
The timers can cover a range from 32us to 524ms for the internal oscillator. Longer delays can be achieved by
using the external clock as an input.
Table 1-3. Timer Values
For design entry, the user can select the source for the clock and the PAC-Designer software will calculate the
appropriate delays in an easy-to-select menu format.
The control inputs for Timer1-Timer4 can be driven by any of the 16 PLD macrocell outputs. The reset for the timers
is a function of the Global Reset pin (RESET), a power-on reset or when the timer gate goes low. The waveforms in
Figure 1-6 show the basic timer start and reset functions. Timer and clock divider values are entered in during the
design phase using PAC-Designer software, simple pull-down menus allow the user to select the clocking mode
and the values for the timers and the PLD clock.
Figure 1-6. Timer Waveforms
1. Timer values based on 250kHz clock.
0.032 ms
0.064 ms
0.128 ms
0.256 ms
0.512 ms
1.024 ms
2.048 ms
4.096 ms
62 kHz
÷ ÷ ÷ ÷ 4
Timer Gate
Timer Output
(From PLD)
(To PLD)
0.064 ms
0.128 ms
0.256 ms
0.512 ms
1.024 ms
4.096 ms
8.192 ms
31.2 kHz
2.048ms
÷ ÷ ÷ ÷ 8
1
Timer
Start
16.384 ms
0.128 ms
0.256 ms
0.512 ms
1.024 ms
4.096 ms
8.192 ms
15.6 kHz
2.048ms
÷ ÷ ÷ ÷ 16
ProgrammableTimer
Timer Period
Delay
16.384 ms
32.768 ms
0.256 ms
0.512 ms
1.024 ms
4.096 ms
8.192 ms
2.048ms
7.8 kHz
÷ ÷ ÷ ÷ 32
Expired
Timer
1-16
16.384 ms
32.768 ms
65.536 ms
0.512 ms
1.024 ms
4.096 ms
8.192 ms
2.048ms
Reset
Timer
3.9 kHz
÷ ÷ ÷ ÷ 64
Timer
Start
131.072 ms
16.384 ms
32.768 ms
65.536 ms
ispPAC-POWR1208 Data Sheet
1.024 ms
4.096 ms
8.192 ms
2.048ms
2 kHz
÷ ÷ ÷ ÷ 128
ProgrammableTimer
Timer Period
Delay
131.072 ms
262.144 ms
16.384 ms
32.768 ms
65.536 ms
4.096 ms
8.192 ms
2.048ms
1 kHz
÷ ÷ ÷ ÷ 256
Expired
Timer
131.072 ms
262.144 ms
524.288 ms
16.384 ms
32.768 ms
65.536 ms
4.096 ms
8.192 ms
0.5 kHz
÷ ÷ ÷ ÷ 512