102
Embedded Modules
© Tibbo Technology Inc.
4.7.1.2
Serial Port and General-purpose I/O Lines
The EM200 features a serial port (RX, TX lines), plus nine general-purpose I/O lines
(GPIO0-8). All of the above lines are of CMOS type. Maximum load current for each
I/O line is 10mA.
The serial port of the EM200 can work in one of the three modes: UART, Wiegand,
or clock/data. All three modes are described in detail in the documentation for the
serial (ser.) object found inside the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual.
Additionally, see the Platform-dependent Programming Information" section inside
the EM200 platform documentation (same manual).
Simplified structure of EM200's I/O lines is shown on the circuit diagram below. All
lines are "quasi-bidirectional" and can be viewed as open collector outputs with
weak pull-up resistor. There is no explicit direction control. To "measure" an external
signal applied to a pin the OUT line must first be set to HIGH. It is OK to drive the
pin LOW externally when the pin outputs HIGH internally.
I/O line control is described in detail in the documentation for the I/O (io.) object
found inside the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual.
4.7.1.3
Flash and EEPROM Memory
The EM200 has 128KBytes of flash memory and 2KBytes of EEPROM memory.
Half of the flash memory (64KB) is used to store the TiOS firmware. When you are
performing a firmware upgrade it is this memory you are saving the firmware binary
into.
The second half of the flash (64KB) is available to your Tibbo BASIC/C application.
The EEPROM is almost fully available to your application, save for a small 8-byte
area called "special configuration area". The EEPROM is accessed through the
storage (stor.) object (see TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual). Details
on the special configuration area are provided in the Platform-dependent
Programming Information section inside the EM200 platform documentation (same
manual).
4.7.1.4
LED Lines
The EM200 has four LED control lines -- SG, SR, EG, and EY. All lines have the same
internal structure and the LEDs should be connected to these lines as shown on the
schematic diagram below. Maximum load for each line is 10mA.