GMS87C4060 Datasheet, PDF (48/102 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS81C4040/87C4060
PRELIMINARY
13. Serial I/O
The Serial I/O circuit is shown in Figure 13-1 .
The Serial I/O circuit consists of the octal counter, SI-
OR(DF_H), SIOM(DE_H). The SIOR register stores received
data or data which will be transfered. The SIOM register
controls serial communication mode, speed, start, etc.
The more details about registers are shown Figure 13-2 .
SIOM [DE_H]
IOSW SM1 SM0 SCK1 SCK0 SIOST SIOSF
SIOR [DF_H] ^{D7 D6 D5 D4 D3 D2 D1 D0}
PS3
PS4
PS5
Exclk
MUX
Control
Circuit
Sclk
Octal counter
IFSIO
Sout
Sin
1
MUX
0
Figure 13-1 Block Diagram of Serial I/O circuit
Control
The GMS81C4040/GMS87C4060 contains a Synchronous
type Serial I/O module.
1. You have to select serial I/O pins by set the SM1~0.
SM1 SM0 Function
00
01
10
11
-
Send
Receive
-
Port select
R21 R22 R23
R21 R22 R23
Sclk Sout R23
Sclk R22 Sin
R21 R22 R23
Note: Sout pin can handle serial data output or serial data
input. You can input serial data to Sout pin when IOSW bit
is 1. But Sin pin is dedicated serial data input pin.
2. You have to select serial communication clock by set the
SCK1~0.
SCK1 SCK0 Selected Clock
0
0
PS3
0
1
PS4
1
0
PS5
1
1
External clock
Ex: Frequency
(f_ex=8MHz)
1uS
2uS
4uS
User define
3. If you want to send data, write it to SIOR. Or not skip
this.
4. Start serial communication by set SIOST(Serial I/O
start, SIOM bit1).
5. After serial communication is completed, SIOSF bit and
interrupt flag IFSIO will be set.
44
PRELIMINARY
Nov. 1999 Ver 1.0