EM78M612
Universal Serial Bus Microcontroller Series
8.2.2 USB Application FIFOs
For USB Application, EM78M612 provides an 8-byte First-In-First-Out (FIFO) buffer for each
endpoint. The buffer cannot be accessed directly. However, a corresponding Data Byte
Pointer register for each endpoint is made available to address the individual byte of the
FIFO buffer. The content of the individual byte will map to a special register.
8.2.3 E2PROM
2
2
Four bytes of E PROM are located in the IOCC ~ IOCF of control register Bank 1. The
stored data of E PROM are not erased when the power is off and can be read and rewritten
by firmware. In some special case of applications, for example, cordless mouse controller,
2
E PROM can store important data, such as the cordless mouse’s device identification
number.
A control register, RES (address : 0x0E in Bank1) controls the E2PROM, that is, to read,
2
write, or to erase the data from E PROM. Writing a command into this register will execute
2
an action to E PROM. The command value is defined in the following table. Note that there
is an execution time lapse for each command. Before writing the next command into the
2
control register, allow enough time for the E PROM to finish processing the previous
command.
Command Value
Action
Read
Execution Time
0B_0000_0000
0B_0000_0001
0B_0000_0010
0B_0000_0011
1ms
Write
9ms
Erase
Disable
128ms
N/A
8.3 I/O Ports
The EM78M612 has up to fifteen General Purposes I/O pins, which are classifies into two
port groups; Port 6 and Port 7. Each pin has an internal resistor that can be individually
selected by user. Notice that Pin 60 is a input only pin.The following describes the important
features of EM78M612 I/O pins.
8.3.1 Programmable Large Current
Port 7 has two pins; P70 and P71 that can drive large current of up to 30mA. The range of
driving current is from 3mA to 30mA, which is programmable. Use IOC8 [0,1] and IOC8 [4,5]
to control the sink current of P70/P71. The default current is 3mA.
This specification may change without further notice.
2004/4/28 V1.1
25
ELAN [ ELAN MICROELECTRONICS CORP ]
