W925E240 Datasheet, PDF (27/73 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925E/C240
SERIAL DATA BUFFER
(initial = 00H) Read Only
Bit:
7
6
5
4
3
2
1
0
SBUF1.7 SBUF1.6 SBUF1.5 SBUF1.4 SBUF1.3 SBUF1.2 SBUF1.1 SBUF1.0
Mnemonic: SBUF1
Address: C1h
SBUF1.7-0: Serial data on the serial port 1 is read from or written to this location. It actually consists of
two separate internal 8-bit registers. One is the receive register, and the other is the
transmit buffer. Any read access gets data from the receive data buffer, while write
access is to the transmit data buffer.
REGULATOR VOLTAGE CONTROL REGISTER
(initial = 00H)
Bit:
7
6
5
4
3
2
1
0
-
-
-
-
REGVC.3 REGVC.2 REGVC.1 REGVC.0
Mnemonic: REGVC
Address: C2h
REGVC.3-0: 4 bits to tune the regulator output voltage.
POWER MANAGEMENT REGISTER
(initial = XXX00001B)
Bit:
7
6
5
4
3
2
1
0
XT/ RG ^{RGMD RGSL X2OFF X1OFF}
-
-
-
Mnemonic: PMR
Address: C4h
XT/ RG :Crystal/RC Oscillator Select. Setting this bit selects crystal or external clock as system clock
source. Clearing this bit selects the on-chip RC oscillator as clock source. X1UP (STATUS.4)
must be set to 1 and X1OFF (PMR.3) must be cleared before this bit can be set. Attempts to
set this bit without obeying these conditions will be ignored.
RGMD: RC Mode Status. This bit indicates the current clock source of micro-controller. When cleared,
CPU is operating from the external crystal or oscillator. When set, CPU is operating from the
on-chip RC oscillator.
RGSL: RC Oscillator Select. This bit selects the clock source following a resume from Power Down
Mode. Setting this bit allows device operating from RC oscillator when a resume from Power
Down Mode. When this bit is cleared, the device will hold operation until the crystal oscillator
has warmed-up following a resume from Power Down Mode.
X2OFF: Set to disable sub-oscillator (32KHz oscillator)
X1OFF:Crystal Oscillator Disable. Setting this bit disables the external crystal oscillator. This bit can
only be set to 1 while the micro-controller is operating from the RC oscillator. Clearing this bit
restarts the crystal oscillator, the X1UP (STATUS.4) bit will be set after crystal oscillator
warmed-up has completed.
※Please insert at least 5 instructions NOP after X2UP = ”1”& Fsys = Fs (CKCON1.0 = “1”, M/S).
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Publication Release Date: July 12, 2005
Revision A10