
III PERIPHERAL BLOCK: INPUT/OUTPUT PORTS
S1C33L01 FUNCTION PART
EPSON
B-III-9-1
III-9 INPUT/OUTPUT PORTS
The Peripheral Block has a total of 42 input/output ports. Although each pin is used for input/output from/to the
internal peripheral circuits, some pins can be used as general-purpose input/output ports unless they are used for the
peripheral circuits.
Input Ports (K Ports)
Structure of Input Port
The Peripheral Block contains 13 bits of input ports (K50 to K54, K60 to K67).
Figure 9.1 shows the structure of a typical input port.
Input interrupt
circuit
Kxx
KxxD
VDDE
1
2
1 AVDD for K50 and K60–K67
2 Available only for K50–K54
VSS
Address
Internal
data
bus
Figure 9.1
Structure of Input Port
Each input-port pin is connected directly to the internal data bus via a three-state buffer. The state of the input signal
when read at an input port is directly taken into the internal circuit as data.
Input-Port Pins
The input pins concurrently serve as the input pins for peripheral circuits, as shown in Table 9.1. Whether they are
used as input ports or for peripheral circuits can be set bit-for-bit using a function select register.All pins not used for
peripheral circuits can be used as general-purpose input ports that have an interrupt function.
Table 9.1
Input Pins
Pin name
I/O
Pull-up
Function
Function select bit
K50/#DMAREQ0
I
Available Input port / High-speed DMA request 0
CFK50(D0)/K5 function select register(0x402C0)
K51/#DMAREQ1
I
Available Input port / High-speed DMA request 1
CFK51(D1)/K5 function select register(0x402C0)
K52/#ADTRG
I
Available Input port / AD converter trigger
CFK52(D2)/K5 function select register(0x402C0)
K53/#DMAREQ2
I
Available Input port / High-speed DMA request 2
CFK53(D3)/K5 function select register(0x402C0)
K54/#DMAREQ3
I
Available Input port / High-speed DMA request 3
CFK54(D4)/K5 function select register(0x402C0)
K60/AD0
I
–
Input port / AD converter input 0
CFK60(D0)/K6 function select register(0x402C3)
K61/AD1
I
–
Input port / AD converter input 1
CFK61(D1)/K6 function select register(0x402C3)
K62/AD2
I
–
Input port / AD converter input 2
CFK62(D2)/K6 function select register(0x402C3)
K63/AD3
I
–
Input port / AD converter input 3
CFK63(D3)/K6 function select register(0x402C3)
K64/AD4
I
–
Input port / AD converter input 4
CFK64(D4)/K6 function select register(0x402C3)
K65/AD5
I
–
Input port / AD converter input 5
CFK65(D5)/K6 function select register(0x402C3)
K66/AD6
I
–
Input port / AD converter input 6
CFK66(D6)/K6 function select register(0x402C3)
K67/AD7
I
–
Input port / AD converter input 7
CFK67(D7)/K6 function select register(0x402C3)
At cold start, all pins are set for input ports Kxx (function select register CFKxx = "0"). When these pins are used for
the internal peripheral circuits, write "1" to CFKxx. For details on pin functions in this case, refer to the description
of each peripheral circuit in this manual.
At hot start, the pins retain their state from prior to the reset.
When the ports set for A/D converter input are read, the value obtained is always "0".