IO Map
The ST I O space ranges from ff 0000 to ff ffff. with MC68000 and MC6800 peripheral internal registers starting at ff faOO and ff fcOO respectively. Accessing reserved I O addresses will result in a bus error. Bit values for various read and or write registers are labeled as active One _Zero always mask out unused field bits . The following is a map of ST I O space ff 8001 R W 1----xxxxl Memory Configuration Video Address Counter Video Address Counter Video Address Counter External Internal...
Busy
TTL levels, active high, 1 Kohm pullup resistor to 5 VDC The ST RS232 interface provides voltage level synchronous or asynchronous serial communication. Five EIA RS232C handshake control signals are supported Request To Send and Data Terminal Ready are transmitted through the YM-2149 PSG I O Port A while Clear To Send, Data Carrier Detect, and Ring Indicator are received through the MK68901 MFP. The MFP USART transmit and receive clock inputs are controlled by the Baud Rate Generator MFP Timer...
Ikbd Matrix Ikbd Matrix Ikbd Matrix Ikbd Matrix Ikbd Mcu 1
Down Switch Left Switch Right Switch Fire Button Power ------- The ST video display interface supports low resolution 320 x 200 or 640 x 200 television receivers and composite monitors, low resolution 320 x 200 or 640 x 200 RGB monitors, and medium resolution 640 x 400 monochrome monitors. Both NTSC and PAL color encoding standards are available in two separate configurations of the video interface hardware. For United States television receivers, the modulated RF display signal is provided on...