| 摘要 |
PURPOSE:To use easily the data supplied to an input/output port to the external data processing by providing a means to the input/output port set between the inside and outside parts to transmit the data supplied from the inside to the inside again. CONSTITUTION:The drain of an output FET21 of an input/output port 18 is connected to an external data bus 19 and to the input of an input buffer 22. The drain of the FET21 is also connected to a power supply VDD via a load resistance 33. Thus the data supplied from the inside is outputted to the bus 19 via a latch circuit 20 and the FET21 and also supplied again to the inside via the buffer 22. |
