User's Manual

HC864-AUTO Hardware User Guide
1vv0300946 Rev.4 – 2012-12-27
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Reserved. Page 20 of 77
4. Hardware Commands
4.1. Turning ON the HC864-AUTO
To turn on HC864-AUTO, the pad ON# must be tied low for at least 1 second and then
released.
The maximum current that can be drained from the ON# pad is 0.1 mA.
A simple circuit to do it is:
4.2. Initialization and Activation state
Upon turning on HC864-AUTO, HC864-AUTO is not activated yet because the boot
sequence of HC864-AUTO is still going on internally. It takes about 10 seconds to complete
the initializing the module internally.
For this reason, it would be useless to try to access HC864-AUTO during a Initialization state
as below. To get the desirable stability, HC864-AUTO needs at least 10 seconds after the
PWRMON goes High.
During the Initialization state, any kind of AT-command is not available. DTE must be
waiting for the Activation state to communicate with HC864-AUTO.