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ASI4U / ASI4U-E / ASI4U-F Datasheet

January 26, 2016

3.3.11. Enhanced LED Status Indication

ASI4U now supports enhanced status indication by two LED outputs. A special mode for direct application of dual

LEDs and the respective different signaling modes are also implemented. Compared to the A²SI, the former

U5RD pin was reassigned as LED2 pin. Thus, compatibility to existing A²SI board layouts is still guaranteed.

However, it will require keeping the LED2 pin disabled (default state at delivery) in order to avoid short-circuiting

U5R to ground. More detailed information on the different signaling schemes and their activation can be found in

section 4.9.

3.3.12. Communication Monitor/Watchdog

Data and parameter communication are continuously observed by a communication monitor. If neither

Data_Exchange nor Write_Parameter calls were addressed to and received by the IC within a time frame of

approximately 41ms, a No Data/Parameter Exchange status is detected and signaled at LED1.

If the respective flags are set in the EEPROM, the communication monitor can also act as communication

watchdog that initiates a complete IC reset after expiration of the watchdog timer. The watchdog mode can also

be activated and deactivated by a signal at parameter port pin P0. See section 4.15 for more detailed information.

3.3.13. Write Protection of ID_Code_Extension_1

As defined in the AS-Interface Complete Specification V3.0, the ASI4U/ASI4U-E/ASI4U-F also supports write

protection for ID_Code_Extension_1. This feature allows the activation of new manufacturer-protected slave

profiles and is enabled by an EEPROM setting. For more details, see section 4.17.

3.3.14. Summary of Master Calls

Table 3.2 and the diagram on the following page show the complete set of Master calls that are decoded by the

ASI4U/ASI4U-E/ASI4U-F in Slave Mode. The "Enter Program Mode" call is intended for programming of the IC by

the slave manufacturer only. It becomes deactivated as soon as the Program_Mode_Disable flag is set in the

“Firmware Area” block of the EEPROM.

Important note regarding full compliance with the AS-Interface Complete Specification: In order to achieve full

compliance to the AS-Interface Complete Specification, the Program_Mode_Disable flag must be set by the

manufacturer of AS-i slave modules during the final manufacturing and configuration process and before an

AS-i slave device is delivered to field application users.

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