Rainbow Electronics T89C5121 - Manual (Page 34)

34
A/T8xC5121
4164G–SCR–07/06
Interrupt Generator There are several sources of interruption but the SCIB macro-cell issues only one inter-
rupt signal: SCIB IT.
Figure 20. SCIB Interrupt Sources
This signal is high level active. One of the sources is able to set up the interrupt signal
and this is the read of the Smart Card Interrupt register by the CPU that clears this
signal.
If during the read of the Smart Card Interrupt register an interrupt occurs, the set of the
corresponding bit into the Smart Card Interrupt register and the set of the interrupt signal
will be delayed after the read access.
Registers There are fourteen registers to control the SCIB macro-cell. They will be described in
the Section “DC/DC Converter”.
Some of the register widths are greater than a byte. Despite the 8 bits access provided
by the BIU, the address mapping of this kind of register respects the following rule:
• The Lowest significant byte register is implemented at the higher address.
This implementation makes access to these registers easier when using high level pro-
gramming language (C,C++).
ESCTBI
CIccER
ESCWTI
ESCRI
ESCPI
ECVccER
Transmit buffer
copied to shift register
Output current
out of range
Output voltage
out of range
Timeout on WT
counter
Complete
transmission
Complete
reception
Parity error
detected
SCIB IT
ESCTI