EM78M612
Universal Serial Bus Microcontroller Series
This specification may change without further notice
. 2004/4/28
V1.1
1
EM78M612
Universal Serial Bus Microcontroller
V1.1
Specification Revision History
Version
Content
Update
1.0
Initial Version
2003/03/05
1.1
Correction for some text in General Description
P2
,rom size 12K2K
Correction for Pin Configuration of EM78M612XBP
P5
ADC Converter Channel Selector Table fixed
P16
,CH1 Reserved
Added PDA Register Description
P20
,IOC9
Correction for EEPROM Function Description
P24
Changes made to PDA Function Description
P29-32
Revised ADC Converter ready bit for ADC Operation
P17
,
P34
,RAS[7]
2004/04/28
EM78M612
Universal Serial Bus Microcontroller Series
This specification may change without further notice
. 2004/4/2
PS/2 Application Support
8
V1.1
2
SPECIFICATION
1 General Description
The EM78M612 is a series of Universal Serial Bus 8-bit RISC Multi-Time Programming
(MTP) microcontrollers. It is specifically designed for USB low speed device application and
to support legacy device such as PS/2 mouse. The EM78M612 also support one device
address and two endpoints. With no firmware involved, these series of microcontrollers can
automatically identify and decode Standard USB Command to EndPoint Zero.
The EM78M612 is implemented on a RISC architecture. It has five-level stack and eight
interrupt sources. The amount of General Input/Output pins is up to 15. Each device has 112
bytes SRAM and is embedded with 4 bytes of E
2
PROM.
The ROM size of the EM78M612 is
2K.
These series of chips have special features that accommodate your needs. These features
are:
Dual Clock mode which allows the device to run on very low power saving frequency
Pattern Detecting Application function which is used in a serial transmission to count
waveform width
Width Modulation that can generate a duty-cycle-programmable signal
AD converter with up to 10 bits resolution.
2 Features
Low-cost solution for low-speed USB devices, such as mouse, joystick, and gamepad.
USB Specification Compliance
Universal Serial Bus Specification Version 1.1
USB Device Class Definition for Human Interface Device (HID), Firmware
Specification Version 1.1
Support 1 device address and 2 endpoints
USB Application
USB protocol handling
USB device state handling
Identifies and decodes Standard USB commands to EndPoint Zero
Auto-detects PS/2 or USB port
Built-in PS/2 port interface
EM78M612
Universal Serial Bus Microcontroller Series
This specification may change without further notice
. 2004/4/28
V1.1
3
Built-in 8-bit RISC MCU
5 level stacks for subroutine and interrupt
8 available interrupts
8-bit real time clock/counter (TCC) with overflow interrupt
Built-in RC oscillator free running for WatchDog Timer and Dual clock mode
Two independent programmable prescalers for WDT and TCC
Two methods of power saving:
1. Power-down mode (SLEEP mode)
2. Low frequency mode.
Two clocks per instruction cycle
Multi-time programmable
I/O Ports
Up to 15 general purposes I/O pins grouped into two ports (Port 6 and 7).
Up to 2 LED sink pins
Each GPIO pin of Ports 6 has an internal programmable pull-high resistor (200K
Ohms)
Each GPIO pin wakes up the MCU from sleep mode by input state change
Internal Memory
Built-in 2048K*13 bits Program ROM
Built-in 112 bytes general purpose registers (SRAM)
Built-in USB Application FIFOs.
Built-in 4 bytes E
2
PROM (EM78M612B, EM78M612D)
Operation Frequency
Normal Mode: MCU runs on the external oscillator frequency
Dual Clock Mode: MCU runs at the frequency of 256KHz (or 32KHz, 4KHz, 500Hz),
emitted by the internal oscillator with the external ceramic resonator (or crystal)
turned off to save power.
Built-in Pattern Detecting Application for serial signal transmission
Built-in Pulse Width Modulation (PWM)
Up to 2 channels PWM function on P.64 (PWM1) and P.65 (PWM2).
Up to 8-bit resolution PWM output
Up to 8 selections of duty cycles
Built-in 15-Channel Analog-to-Digital Converter (ADC)
Built-in AD Converter with 10-bit resolution
EM78M612
Universal Serial Bus Microcontroller Series
This specification may change without further notice
. 2004/4/28
V1.1
4
4 ADC conversion rates: 256K/128K/64K/32K
Built-in 3.3V Voltage Regulator
For MCU power supply
Pull-up source for the external USB resistor on D-pin.
Package Type
16 pin PDIP/SOP (EM78M612(A/B/C/D) A P/M)
18 pin PDIP/SOP (EM78M612(A/B/C/D) B P/M)
20 pin PDIP/SOP (EM78M612(A/B/C/D) C P/M)
20 pin SSOP (EM78M612(A/B/C/D) EM)
24 pin PDIP/SOP (EM78M612(A/B/C/D) D P/M)
24 pin SSOP (EM78M612(A/B/C/D) FM)
3 Type Definition
The EM78M612 series has sereval types of packaging. Each type is divided into 4 modules,
namely; original, with E
2
PROM, with A/D converter, and with both E
2
PROM and A/D
converter. Hence, packaging configuration for each series is defined. The Table 3.1 below
summarizes which series of the EM78M612 belong to which module.
Original
With E
2
PROM
With A/D
Converter
With Both
EM78M612A EM78M612B
EM78M612C
EM78M612D
Table 3-1 Packaging Summary of EM78M612 Series IC
EM78M612
Universal Serial Bus Microcontroller Series
This specification may change without further notice
. 2004/4/28
V1.1
5
4 Applications
This microcontroller is designed for USB low speed device application or non-USB
embedded device. It is also suitable for PS/2 mouse application.
5 Pin Configuration
P61
1
16 P60/V
PP
P62
2
15
P64
P63
3
14
P65
P70
4
13
P71
V
SS
5
12 D+/P50
V
NN
6
11
D-/P51
V
3.3V
7
10
V
DD
OSCI
8
9
OSCO
EM78M612XAP
P60/V
PP
1
20
P64
P61
2
19
P65
P62
3
18
P66
P63
4
17
P67
P70
5
16
P71
P72
6
15
P73
V
SS
7
14
D+/P50
V
NN
8
13
D-/P51
V
3.3V
9
12
V
DD
OSCI
10
11
OSCO
EM78M612XCP
P60/V
PP
1
18
P64
P61
2
17
P65
P62
3
16
P66
P63
4
15
P67
P70
5
14
P71
V
SS
6
13 D+/P50
V
NN
7
12
D-/P51
V
3.3V
8
11
V
DD
OSCI
9
10
OSCO
EM78M612XBP
P60/V
PP
1
24
P64
P61
2
23
P65
P62
3
22
P66
P63
4
21
P67
P70
5
20
P71
P72
6
19
P73
P74
7
18
P75
P76
8
17
P77
V
SS
9
16
D+/P50
V
NN
10
15
D-/P51
V
3.3V
11
14
V
DD
OSCI
12
13
OSCO
EM78M612XDP
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