Microchip Technology ADM00421 Data Sheet

DS22288A-page 8

 2011 Microchip Technology Inc.

The EEPROM module is a 256-byte array of nonvola-
tile memory. The memory locations are accessed for
read/write operations solely via USB host commands.
The memory cells for data EEPROM are rated to
endure thousands of erase/write cycles, up to 100K for
EEPROM. 
Data retention without refresh is conservatively
estimated to be greater than 40 years.

1.8.1

RESET PIN

The RST pin provides a method for triggering an
external Reset of the device. A Reset is generated by
holding the pin low. MCP2210 has a noise filter in the
Reset path which detects and ignores small pulses.

1.8.2

POR

A POR pulse is generated on-chip whenever V

DD

 rises

above a certain threshold. This allows the device to
start in the initialized state when V

DD

 is adequate for

operation.
To take advantage of the POR circuitry, tie the RST pin
through a resistor (1 k

 to 10 k) to V

DD

. This will

eliminate external RC components usually needed to
create a POR delay.
When the device starts normal operation (i.e., exits the
Reset condition), the device operating parameters
(voltage, frequency, temperature, etc.) must be met to
ensure operation. If these conditions are not achieved,
the device must be held in Reset until the operating
conditions are met.

The input clock must be 12 MHz to provide the proper
frequency for the USB module. USB full-speed is
nominally 12 Mb/s. The clock input accuracy is ±0.25%
(2,500 ppm maximum).

Quartz Crystal

12 MHz

OSC1

OSC2

R

S

R

F

Note 1: A series resistor (R

S

) may be required for

quartz crystals with high drive level.

2: The value of R

F

 is typically between 2 M

 to

10 M

..

Example: muRata

®

 

CSTCE12M0G15L

OSC1

OSC2

Resonator

12 MHz