GD32F403xx User Manual
233
Figure 14-1. Free watchdog block diagram
IRC40K
Reset
Prescaler
/4/8
/256
12-Bit
DownCounter
Reload
register
Control
register
Reload
Status: PUD
Status: RUD
The f ree watchdog is enabled by writing the value (0xCCCC) to the control register
(FWDGT_CTL), then the counter starts counting down. When the counter reaches the value
(0x000), there will be a reset.
The counter can be reloaded by writing the value (0xAAAA) to the FWDGT_CTL register at
anytime. The reload value comes from the FWDGT_RLD register. The software can prevent
the watchdog reset by reloading the counter before the counter reaches the value (0x000).
The f ree watchdog can automatically start when power on if the hardware free watchdog bit
in the device option bits is set. To avoid a reset, the software should reload the counter before
the counter reaches (0x000).
The FWDGT_PSC register and the FWDGT_RLD register are written protected. Before
writing these registers, the software should write the value (0x5555) to the FWDGT_CTL
register. These registers will be protected again by writing any other value to the
FWDGT_CTL register. When an update operation of the prescaler register (FWDGT_PSC)
or the reload value register (FWDGT_RLD) is ongoing, the status bits in the FWDGT_STAT
register are set.
If the FWDGT_HOLD bit in DBG module is cleared, the FWDGT continues to work even the
Cortex
®
-M4 core halted (Debug mode). The FWDGT stops in Debug mode if the
FWDGT_HOLD bit is set.
Table 14-1. Min/max FWDGT timeout period at 40 kHz (IRC40K)
Prescaler divider
PSC[2:0] bits
Min timeout (ms)
RLD[11:0]=0x000
Max timeout (ms)
RLD[11:0]=0xFFF
1 / 4
000
0.025
409.525
1 / 8
001
0.025
819.025
1 / 16
010
0.025
1638.025
1 / 32
011
0.025
3276.025
1 / 64
100
0.025
6552.025
1 / 128
101
0.025
13104.025
Содержание GD32F403 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F403xx Arm Cortex M4 32 bit MCU User Manual Revision 2 6 Jul 2022 ...
Страница 177: ...GD32F403xx UserManual 177 Peripheral Channel 0 Channel 1 Channel 2 Channel 3 Channel 4 SDIO SDIO ...
Страница 217: ...GD32F403xx UserManual 217 ensures that no conversion is in progress ...