C8051T322-GQR Silicon Labs, C8051T322-GQR Datasheet - Page 127

• Manufacturer Part Number: C8051T322-GQR
• Description: 8-bit Microcontrollers - MCU USB-OTP-16K-LQFP32
• Manufacturer: Silicon Labs

Specifications of C8051T322-GQR

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

21.4. Clock Multiplier
The C8051T620/621/320/321/322/323 device includes a 48 MHz high-frequency oscillator instead of a
12 MHz oscillator and a 4x Clock Multiplier, so the USB0 module can be run directly from the internal high-
frequency oscillator. For compatibility with the Flash development platform, however, the CLKMUL register
(SFR Definition 21.4) behaves as if the Clock Multiplier is present.
SFR Definition 21.4. CLKMUL: Clock Multiplier Control
SFR Address = 0xB9
Name
Reset
Bit
4:2
1:0 MULSEL[1:0] Clock Multiplier Input Select Bits.
Type
7
6
5
Bit
MULRDY
MULINIT
MULEN
Unused
MULEN
Name
R
7
1
Clock Multiplier Enable Bit.
0: Clock Multiplier disabled.
1: Clock Multiplier enabled.
This bit always reads 1.
Clock Multiplier Initialize
Bit.
Clock Multiplier Ready Bit.
0: Clock Multiplier not ready.
1: Clock Multiplier ready (locked).
This bit always reads 1.
Unused. Read = 000b; Write = Don’t Care
These bits select the clock supplied to the Clock Multiplier.
00: Internal High-Frequency Oscillator
01: External Oscillator
10: External Oscillator/2
11: Reserved.
These bits always read 00.
MULINIT
R
6
1
Description
MULRDY
R
5
1
C8051T620/621/320/321/322/323
Rev. 1.1
R
4
0
This bit should be a 0
when the Clock Multiplier
is enabled. Once
enabled, writing a 1 to
this bit will initialize the
Clock Multiplier.
R
Write
3
0
R
2
0
The MULRDY bit reads 1
when the Clock Multiplier
is stabilized.
This bit always reads 1.
1
MULSEL[1:0]
0
Read
R
0
0
127