GMS81508B HYNIX [Hynix Semiconductor], GMS81508B Datasheet - Page 53

• Manufacturer Part Number: GMS81508B
• Description: HYUNDAI MICRO ELECTRONICS 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: HYNIX [Hynix Semiconductor]

GMS81508B/16B/24B
13.1 Transmission/Receiving Timing
The serial transmission is started by setting SIOST(bit1 of
SIOM) to “1”. After one cycle of SCK, SIOST is cleared
automatically to “0”. The serial output data from 8-bit shift
register is output at falling edge of SCLK. And input data
13.2 The Serial I/O operation by SRDY pin
Transmission clock = external clock
The SRDY pin becomes “L” by SIOST = “1”. This signal
tells to the external system that this device is ready for se-
Transmission clock = internal clock
The I/O of SRDY pin is input mode. When the external
system is ready for serial transmission, The “L” level is in-
50
Input Clock
SCLK PIN
SIOST FLAG
SIOIF
INTERRUPT SIGNAL
SOUT PIN
SIN PIN
SIOST
SIOST
SRDY(Output)
SRDY(Input)
Figure 13-3 Timing Diagram of Serial I/O
D 0
D 0
Latch
Output
D 1
D 1
D2
D2
D3
D3
is latched at rising edge of SCLK pin. When transmission
clock is counted 8 times, serial I/O counter is cleared as
‘0”. Transmission clock is halted in “H” state and serial I/
O interrupt(IFSIO) occurred.
rial transmission. The external system detects the “L” sig-
nal and starts transmission. The SRDY pin becomes “H” at
the first rising edge of transmission clock.
putted at this pin. At this time this device starts serial trans-
mission.
D4
D4
D5
D5
D6
D6
HYUNDAI MicroElectronics
D7
D7
DEC. 1999 Ver 1.04