sh6613 SinoWealth Micro-Electronics Corp. Ltd, sh6613 Datasheet - Page 7

• Manufacturer Part Number: sh6613
• Description: 4k 4-bit Microcontroller With Lcd Driver
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

5.4 Control of oscillator
The oscillator control register configuration is shown as blow.
OXON: OSCX oscillation on/off.
OXM: switching system clock.
OXS: OSCX oscillator type selection
5.5 Programming notes
It takes at least 5 ms for the OSCX oscillation circuit to go on until the oscillation stabilizes. When switching the CPU system
clock from OSC to OSCX, you must wait a minimum of 5ms since the OSCX oscillation goes. However, the start time varies a lot
with respect to oscillator characteristics and the condition of use. So the waiting time depends on applications. When switching
from OSCX to OSC, and turn off OSCX in one instruction. The OSCX turn off control would be delayed for one instruction cycle
automatically to prevent CPU operation error.
6. System clock
The system clock is varies as the clock source changes. The following table shows the instruction execution time according to
each frequency of the system clock source.
Cycle time
7. I/O PORTs
The MCU provides 8-bidirectional I/O pins. Each I/O pin contains pull-up MOS controllable by program. When every I/O is used
as input, the PORT control register (PACR, PBCR) controls ON/OFF of the output buffer.
7.1 PORTA~B
These ports contain 8-bidirectional I/O ports.
The circuit configuration of PORTA~B as below.
I/O ports of SH6613/B/C can be accessed by read/write system register.
User can output any value to any I/O port bit at any time.
Memory map addresses are listed as follow:
Address
$08
$09
Add.
$14
0:Turn off OSCX oscillation
0:select OSC as system clock
0:OSCX set as ceramic oscillator
32.768 Xtal(OSC )
122.07 µ s
OXS
Bit3
Bit3
PORTA.3
PORTB.3
REGISTER
CONTROL
REGISTER
262K RC(OSC )
17.778 µ s
PULLUP
DATAINPUT
PORT
PORT
DATA
Bit2
-
Bit2
PORTA.2
PORTB.2
1:Turn on OSCX oscillation
1:select OSCX as system clock
1:OSCX set as RC oscillator
455K ceramic Xtal(OSCX)
8.79 µ s
OXM
Bit1
7/33
RD_INPUT
OXON
Bit0
Bit1
PORTA.1
PORTB.1
PULL_UP
PMOS
1.8M RC(OSCX)
2.22 µ s
PORTX
Bit0
PORTA.0
PORTB.0
SH6613/B/C
2M RC(OSCX)
2 µ s
V1.2