sh6614d SinoWealth Micro-Electronics Corp. Ltd, sh6614d Datasheet - Page 10

• Manufacturer Part Number: sh6614d
• 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 follows:
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 turn on until the oscillation stabilizes. When switching the CPU system
clock from OSC to OSCX, the user must wait a minimum of 5ms since the OSCX oscillation is running. However, the start time
varies with respect to oscillator characteristics and the condition of use. Thus the wait time depends on the application. When
switching from OSCX to OSC, and turning off OSCX in one instruction. The OSCX turn off control will be delayed for one
instruction cycle automatically to prevent CPU operation error.
6. System clock
The system clock varies as the clock source changes. The following table shows the instruction execution time according to
each frequency of the system clock source.
7. I/O PORTs
The MCU provides 8bi-directional I/O pins. Each I/O pin contains pull-up MOS controllable through programming. When every
I/O is used as input, the PORT control register (PACR, PBCR) controls the ON/OFF of the output buffer.
7.1. PORTA - B
These ports contain 8bi-directional I/O ports.
The circuit configuration of PORTA - B as is shown as:
I/O ports of SH6614D can be accessed by the read/write system register.
User can output any value to any I/O port bit at any time.
Memory map addresses are listed as follows:
Cycle time
Address
Address
$14
0: Turn-off OSCX oscillation
0: select OSC as system clock
0: OSCX set as ceramic oscillator
$08
$09
32.768 Xtal (OSC )
122.07 µ s
OXS
Bit3
PORTA.3
PORTB.3
Bit3
REGISTER
CONTROL
REGISTER
PULLUP
DATAINPUT
PORT
262K RC (OSC )
PORT
DATA
17.778 µ s
Bit2
-
PORTA.2
PORTB.2
Bit2
1: Turn-on OSCX oscillation
1: select OSCX as system clock
1: OSCX set as RC oscillator
455K ceramic Xtal (OSCX)
OXM
Bit1
10
8.79 µ s
PORTA.1
PORTB.1
RD_INPUT
Bit1
OXON
Bit0
PULL_UP
PMOS
PORTX
1.8M RC (OSCX)
PORTA.0
PORTB.0
2.22 µ s
Bit0
2M RC(OSCX)
SH6614D
2 µ s