C8051T622-GMR Silicon Labs, C8051T622-GMR Datasheet - Page 80

• Manufacturer Part Number: C8051T622-GMR
• Description: 8-bit Microcontrollers - MCU USB-OTP-16K-QFN24
• Manufacturer: Silicon Labs

Specifications of C8051T622-GMR

• Rohs: yes
• Core: 8051
• Data Bus Width: 8 bit
• Processor Series: C8051

C8051T622/3 and C8051T326/7
15. Reset Sources
Reset circuitry allows the controller to be easily placed in a predefined default condition. On entry to this
reset state, the following occur:




All SFRs are reset to the predefined values noted in the SFR detailed descriptions. The contents of internal
data memory are unaffected during a reset; any previously stored data is preserved. However, since the
stack pointer SFR is reset, the stack is effectively lost, even though the data on the stack is not altered.
The Port I/O latches are reset to 0xFF (all logic ones) in open-drain mode. Weak pullups are enabled dur-
ing and after the reset. For V
exits the reset state.
On exit from the reset state, the program counter (PC) is reset, and the system clock defaults to the inter-
nal oscillator. The Watchdog Timer is enabled with the system clock divided by 12 as its clock source. Pro-
gram execution begins at location 0x0000.
80
XTAL1
XTAL2
CIP-51 halts program execution
Special Function Registers (SFRs) are initialized to their defined reset values
External Port pins are forced to a known state
Interrupts and timers are disabled.
Frequency
Oscillator
Oscillator
Oscillator
External
Internal
Drive
Low
Clock Select
System
Clock
DD
Monitor and power-on resets, the RST pin is driven low until the device
Detector
Figure 15.1. Reset Sources
Missing
Clock
(one-
shot)
Microcontroller
EN
Extended Interrupt
CIP-51
Core
Handler
WDT
PCA
EN
Rev. 1.1
VDD
System Reset
Supply
Monitor
+
-
Enable
(Software Reset)
SWRSF
0
Power On
Reset
Errant EPROM
Operation
(wired-OR)
Reset
Funnel
RST