AN1313 - APPLICATION NOTE

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4 - MODIFIED REGISTERS

4.1 - PICON Register

Some bits have been added, and some suppressed in this register for the ST10F269.

The Port Input Control register PICON is used to select between TTL and CMOS-like input thresholds.

The CMOS-like input thresholds are defined above the TTL levels and feature a defined hysteresis to

prevent the inputs from toggling while the respective input signal level is near the thresholds.

In the ST10F168, these functionality is available for all pins of Port 2, Port 3, Port 7 and Port 8.

In the ST10F269, this functionality has been added for the pins of Port 4.

It is also used to select the Output driver characteristics of some pins of the ST10F168 but no longer on

the ST10F269 where the POCONx registers have been added for this purpose (see New Registers

section).

ST10F168: PICON (F1C4h / E2h)

ESFR

Reset Value: 0000h

ST10F269: PICON (F1C4h / E2h)

ESFR

Reset Value: 0000h

4.1.1 - Hardware Impacts

None.

4.1.2 - Software Impacts

The initialization of the PICON register is impacted. Moreover some other registers will have to be

configured.

The initialization of the output driver characteristic has to be done through the POCON registers and the

high byte of the PICON register is reserved on the ST10F269. Check that the ST10F168 software was

not writing in bit4 of PICON which is no longer reserved on the ST10F269.

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

P8LOUT P7LOUT

-

-

P3HOUT P3LOUT P2HOUT P2LOUT P8LIN P7LIN

-

-

P3HIN P3LIN P2HIN P2LIN

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

RW

15

14

13

12

11

10

9876543210

--------

P8LIN

P7LIN

-

P4LIN

P3HIN

P3LIN

P2HIN

P2LIN

RW

RW

RW

RW

RW

RW

RW

Bit Name

Function

PxLIN

0

1

Port x Low Byte Input Level Selection

Pins P2.7...P2.0 switch on standard TTL input levels

Pins P2.7...P2.0 switch on special threshold input levels

PxHIN

Port x High Byte Input Level Selection

P4LIN

Port 4 Input Level Selection

Added on

ST10F269

PxLOUT

0

1

Port x Low Byte Output Driver Characteristic Selection

Pins Px.7...0 output driver strength is reduced after reaching VOL or VOH

Pins Px.7...0 output drive is not reduced after reaching VOL or VOH

Only for ST10F168

PxHOUT

0

1

Port x High Byte Output Driver Characteristic Selection

Pins Px.15...8 output driver strength is reduced after reaching VOL or VOH

Pins Px.15...8 output drive is not reduced after reaching VOL or VOH

Only for ST10F168