AT83EC5123 ATMEL Corporation, AT83EC5123 Datasheet - Page 55

• Manufacturer Part Number: AT83EC5123
• Description: (AT8xx512x) Smart Card Reader ICs
• Manufacturer: ATMEL Corporation

Initialization Procedure
4202B–SCR–07/03
mode by 20% by means of bit OVFADJ in DCCKPS register. When the current overflow
controller is operating, the ICARDOVF is set by the hardware in SCISR register.
The current drawn from power supply by the DC/DC converter is controlled during the
startup phase in order to avoid high transient current mainly in Pump Mode which could
cause the power supply voltage to drop dramatically. This control is done by means of
bits BOOST[1:0], which increases progressively the startup current level.
The initialization procedure is described in flow chart of Figure 29.
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•
•
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Figure 29. DC/DC Converter Initialization Procedure
While VCC remains higher than 3.6V and startup current lower than 30 mA (depending
on the load type), the DC/DC converter should be ready without having to increment
Select the CVCC level by means of bits VCARD[1:0] in SCIIR register,
Set bits BOOST[1:0] in DCCKPS register following the current level control wanted.
Switch the DC/DC on by means of bit CARDVCC in SCCON register,
Monitor bit VCARDOK in SCISR register in order to know when the DC/DC
Converter is ready (CVCC voltage has reached the expected level)
Set Timeout to 3 ms
Initialization Failure
BOOST[1:0]=[0:0]
DC/DC Converter
BOOST[1:0] is
VCARDOK=1
at Maximum?
BOOST [1:0]
Increment
Timeout
Expired
END
current overflow
BOOST[1:0]
to adjust the
AT8xC5122/23
Decrement
END
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