Appendix
Appendix
User's Manual
BAB 740
7—3
7.1.2 Enhanced Serial Communications
Controller (ESCC)
In addition to the two serial controllers COM1 and COM2 that are
incorporated in the PC97307 Super-I/O the BAB 740 features
another two serial lines that are realized with a Z85230 ESCC. The
ESCC is clocked with 12 MHz or 14.7456 MHz. This allows transfer
rates up to 3 MBaud synchronous and 230.4 KBaud asynchronous.
Channel A can be operated with DMA to reduce interrupt load of the
CPU for synchronous block protocols. DMA channel 0 is used for
receive and Channel 1 for transmit. The DMA controller must be
programmed to type A or B mode. The Interrupt request of the
ESCC is connected to INT9 input of the interrupt controller.
Table 31: ESCC Address Assignment:
I/O Address Description
$800 ESCC Channel B Control
$801 ESCC Channel A Control
$802 ESCC Channel B Data
$803 ESCC Channel A Data
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