AN2169

New registers

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4.2.2

Software Impact

Once the XPEN bit of SYSCON register is set and at least one of the X-peripherals (except

memories) is activated, the register XPEREMU must be written with the same content of

XPERCON: this is mandatory in order to allow a correct emulation of the new set of features

introduced on X-BUS for the new ST10 generation. The following instructions must be added

inside the initialization routine:

if (SYSCON.XPEN && (XPERCON & 0x07D3))

then { XPEREMU = XPERCON }

Of course, XPEREMU must be programmed after XPERCON and after SYSCON, in such a

way the final configuration for X-Peripherals is stored in XPEREMU and used for the emulation

hardware setup.

4.3

EXISEL register

This register, standing for External Interrupt source selection, has been added in the

ST10F276.

The purpose of this new register is to select the interrupt sources of the fast external interrupts

among the other peripherals. For example, the CANy controller receive signal (CANy_RxD) can

be used to interrupt the system(y=1,2).

ST10F276: EXISEL (F1DAh / EDh)

SFR

Reset Value: -005h

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

EXI7SS

EXI6SS

EXI5SS

EXI4SS

EXI3SS

EXI2SS

EXI1SS

EXI0SS

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

Bit name

Function

EXIxSS

External Interrupt x source Selection (x=7..0)

00: Input from associated Port 2 pin.

01: Input from "alternate source".

10:Input from associated Port 2 pin logically ORed with "alternate source".

11:Input from associated Port 2 pin logically ANDed with "alternate source".

EXIxSS

Port 2 pin

Alternate source

0

P2.8

CAN1_RxD

P4.5

1

P2.9

CAN2_RxD / SCL

P4.4

2

P2.10

RTC_secIT

Internal MUX

3

P2.11

RTC_alarmIT

Internal MUX

4..7

P2.12..P2.15

Not used (zero)

-