
AS-Interface Slave IC
AS2702 (SAP4.1)
Rev. C, January 2001 Page 13 of 18
Symbol Parameter min. max. Unit Note
ILED Sink current @ output L 10 mA VOUT = 1V
IOUTHI Leackag e cur r ent @ output off - 10 10 µA VOUT = 5V
VIN Accept able input voltage @ out-
put of f - 0.3 40 V
fBLI NK Blinking frequency 2 3 Hz
Data Communication Watchdog
AS2702 is equipped with a watchdog timer t o super vise data comm unication by monitoring
the strobe signals at pins DSTBn and PSTBn.
If a par am eter or data str obe is not followed by a consecutive str obe within a time per iod of
50 … 100 ms, the watchdog is trigger ed and initiates a ‘soft ’ reset, see section ‘Reset’
RESET
There are 2 categories of r eset-events, leading to 2 slightly different reset- conditions of the
slave device:
1) a ‘hard’ reset t aking place at power-up and power-down of supply-voltages U5R and
UOUT.
At power-up the slave device leaves reset-condition as soon as U5R has passed 3.75V
and UOUT has passed VCO MOFF = nom. 10V.
At power-down the slave device is forced into reset - condition as soon as U5R drops below
3.75V.
(Tolerance of the threshold voltages referr ed to is -/+ 5%.)
2) a ‘soft ’ re set , resulting from one of the following events:
2.1) Data st robe pin DSTBn is kept L for more than 100 ms;
2.2) Master comm and ‘RESET SLAVE’ is received;
2.3) Master command ‘RESET BROADCAST’ is received;
2.4) T he com m unicat ion watchdog is t riggered.
A ‘hard’ reset event condit ions t he slave device as follows:
• Internal states (counters, flags, …) are r eset
• The slave device’s receiver is desynchronized from the AS-interf ace bus
• The low-side open-drain output stages at ports D3, …, D0 and ports P3, …, P0 are
switched off
• Any test-mode will be cancelled.
A ‘soft ’ reset has the following consequences:
• A regular , nom inal 6µs L-phase strobe is gener at ed on bot h the DSTBn and PSTBn pin
• The low-side open-drain output stages at ports D3, …, D0 and ports P3, …, P0 are
switched off
• Internal st at es ( c ount er s, flags, …) ar e r eset , however the following states and operations
are not affected:
• the timer function which controls blinking of LED1 and LED2
• the data communication watchdog
• any testmode
• any EEPROM write operat ion.
Remark: