SAA-XC866-1FRA INFINEON [Infineon Technologies AG], SAA-XC866-1FRA Datasheet - Page 59

• Manufacturer Part Number: SAA-XC866-1FRA
• Description: 8-Bit Single-Chip Microcontroller
• Manufacturer: INFINEON [Infineon Technologies AG]

SAA-XC866
Functional Description
3.7
Reset Control
The SAA-XC866 has five types of reset: power-on reset, hardware reset, watchdog timer
reset, power-down wake-up reset, and brownout reset.
When the SAA-XC866 is first powered up, the status of certain pins (see
Table
19) must
be defined to ensure proper start operation of the device. At the end of a reset sequence,
the sampled values are latched to select the desired boot option, which cannot be
modified until the next power-on reset or hardware reset. This guarantees stable
conditions during the normal operation of the device.
In order to power up the system properly, the external reset pin RESET must be asserted
until V
reaches 0.9*V
. The delay of external reset can be realized by an external
DDC
DDC
capacitor at RESET pin. This capacitor value must be selected so that V
reaches
RESET
0.4 V, but not before V
reaches 0.9* V
DDC
DDC.
A typical application example is shown in
Figure
21. V
capacitor value is 300 nF.
DDP
V
capacitor value is 220 nF. The capacitor connected to RESET pin is 100 nF.
DDC
is less than 50 μs once V
Typically, the time taken for V
to reach 0.9*V
DDC
DDC
DDP
reaches 2.3V. Hence, based on the condition that 10% to 90% V
(slew rate) is less
DDP
than 500 μs, the RESET pin should be held low for 500 μs typically. See
Figure
22.
3.3/5V
220nF
e.g. 300nF
VDDC
VSSC
VSSP
VDDP
typ.
RESET
100nF
EVR
30k
XC866
Figure 21
Reset Circuitry
Data Sheet
56
V1.5, 2010-09