AMIS-30522 Datasheet, PDF (16/28 Pages) AMI SEMICONDUCTOR – Micro-stepping Motor Driver

AMIS-30522 Micro-stepping Motor Driver
Data Sheet
In case the timer is activated and WDEN is acknowledged too early (before t_WDPR) or not within the interval (after t_WDTO), then a reset of
the microcontroller will occur through PORB/WD pin. In addition, a warm/cold boot bit <WD> is available in Table 29: SPI Status
Register 0 for further processing when the external microcontroller is alive again.
VBB
VDD
tPU
VDDH
POR/WD pin
tPOR
tDSPI
t
t
tWDRD _tPOR
Enable WD
> tWDPR and < tWDTO
Acknowledge WD
t
tWDTO
= tWDPR or = tWDTO
WD timer
Figure 15: Watchdog Timing Diagram
t
PC20070604.9
Note: t_DSPI is the time needed by the external microcontroller to shift-in the <WDEN> bit after a power-up.
The duration of the watchdog timeout interval is programmable through the WDT[3:0] bits (Table 14: SPI Control Register WR). The
timing is given in Table 13.
Table 13: Watchdog Timeout Interval as Function of WDT[3.0]
Index
WDT[3:0]
t_WDTO (ms)
0
0 0 0 0 32
1
0 0 0 1 64
2
0 0 1 0 96
3
0 0 1 1 128
4
0 1 0 0 160
5
0 1 0 1 192
6
0 1 1 0 224
7
0 1 1 1 256
8
1 0 0 0 288
9
1 0 0 1 320
A
1 0 1 0 352
B
1 0 1 1 384
C
1 1 0 0 416
D
1 1 0 1 448
E
1 1 1 0 480
F
1 1 1 1 512
AMI Semiconductor – June 2007, M-20684-001
16
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