Epson S1C33210 - Manual (Page 364)

III PERIPHERAL BLOCK: INPUT/OUTPUT PORTS
B-III-9-2 EPSON S1C33210 FUNCTION PART
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)
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)
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".
Notes on Use
The input buffers of the K60 to K63 ports use AV DD (power voltage for A/D converter) as their power source.
Therefore, the following precautions must be taken.
1) When using K60–K63 as general-purpose input ports, the voltage input to the port must be high level = AV DD and
low level = V SS .
2) When using V DD as high level similar to other ports, V DD must be the same voltage level as AV DD . If the input
V DD level is lower than the AV DD level, current flows in the input buffer, or if the input V DD level is higher than
the AV DD level, current flows from the V DD power supply to the AV DD power supply.
3) To fix the input level externally when the port is not used, the input pin should be connected to V SS or AV DD .