AS8267 datasheet(110/136 Pages) AMSCO

110 / 136 page

Data Sheet AS8267 / AS8268

Revision 1.0, 19-Jun-07

Page 110 of 136

8.9

System Control (SCT)

The system control is responsible for handling different modes of operation such as normal mode (metering

functions) and test mode.

The clock generation and reset control are also available in System Control (SCT).

Modes of Operation

Power off

In this mode everything is off including the ‘System Timing and RTC’ block, provided that no battery is

connected to VDD_BAT or the battery is discharged. Nothing happens.

RTC on, Rest of the Chip off

In this mode the ‘System Timing and RTC’ block is supplied by a battery, the RTC is working, but no interrupts

are generated.

At the moment the battery is inserted, a power-on reset just for the RTC will be generated. The reset will be set

to 0 after the first clock edges arrive.

Power-up Phase

When the power is switched on (for the ‘rest’ of the chip), there is a power-on reset first and the reset is held

until the BOOTLOAD block has finished operation. The BOOTLOAD block will load information from the upmost

page (program available, security) from the internal Flash memory.

After BOOTLOAD the MCU will start executing the program in the Flash memory. It is assumed that at the

beginning of the program various system parameters are set (sel_i, sel_v, sel_p, creep etc.)

FLASH not programmed, must be loaded from outside

If the Flash does not contain a program the MCU will run in idle mode. It is necessary to write a program to the

Flash next.

Reset Chip: Externally triggered BOOTLOAD

When a (new) program has been written to the Flash it will be necessary to trigger a new BOOTLOAD

sequence. This can be done by generating a chip reset. After the related command has been detected by the

SCT on the UART1 interface the reset/boot sequence will start. Next the MCU will run the program from the

beginning.

This command can also be used for a simple reset.

Normal Operation

The MCU is working through its program, access to certain blocks/functions may be done via the UART

interfaces. For example, it may be required to read data from an external EEPROM or from the RTC block.

During these operations the MCU is not reset!

AS8267 Datasheet(PDF) 110 Page - ams AG