SMM764
Preliminary Information
I2C PROGRAMMING INFORMATION (CONTINUED)
WRITE PROTECTION
The slave address and bus address must be set each
time the memory is accessed. Memory writes and
reads are shown in Figures 19, 20 and 21.
COMMAND AND STATUS REGISTERS
The SMM764 powers up into a write protected mode.
Writing a code to the volatile write protection register
can disable the write protection. The write protection
register is located at address 87HEX of slave address
The command and status registers are located at
1001BIN
.
slave address 1001BIN
.
Writes and reads of the
Writing 0101BIN to bits [7:4] of the write protection
register allow writes to the general-purpose memory
while writing 0101BIN to bits [3:0] allow writes to the
configuration registers. The write protection can re-
enable by writing other codes (not 0101BIN) to the write
protection register. Writing to the write protection
register is shown in Figure 13.
command and status registers are shown in Figures
22 and 23.
ADC CONVERSIONS
An ADC conversion on any monitored channel can be
performed and read over the I2C bus using the ADC
read command. The ADC read command, shown in
Figure 24, starts with a dummy write to the 1001BIN
slave address. Bits [6:3] of the word address byte are
used to address the desired monitored input. Once
the device acknowledges the channel address, it
begins the ADC conversion of the addressed input.
This conversion requires 70µs to complete. During
this conversion time, acknowledge polling can be
used. The SMM764 will not acknowledge the address
bytes until the conversion is complete. When the
conversion has completed, the SMM764 will
acknowledge the address byte and return the 10-bit
conversion along with a 4-bit channel address echo.
CONFIGURATION REGISTERS
The majority of the configuration registers are grouped
with the general-purpose memory located at either
slave address 1010BIN or 1011BIN. Bus address bits
BA[2:1] are programmable. The bus address bit BA[0],
however, is used to differentiate the general-purpose
memory from the configuration registers and should be
set to 1BIN when accessing the configuration registers.
Bus address bit BA[2] can be programmed as a
“virtual 0” or biased by the A2 pin.
An additional configuration register is located at
address 84HEX of slave address 1001BIN
.
GRAPHICAL USER INTERFACE (GUI)
Writing and reading the configuration registers is
Device configuration utilizing the Windows based
SMM764 graphical user interface (GUI) is highly
recommended. The software is available from the
Summit website (website at:
shown in Figures 14, 15, 16, 17, and 18
Note: Configuration writes or reads of registers 00HEX
to 0FHEX should not be performed while the SMM764 is
margining.
(http://www.summitmicro.com/tech_support/tech.htm#
GUI.
GENERAL-PURPOSE MEMORY
Using the GUI in conjunction with this datasheet
simplifies the process of device prototyping and the
The 2k-bit general-purpose memory is located at
either slave address 1010BIN or 1011BIN. Bus address
bits BA[2:1] are programmable. The bus address bit
BA[0], however, is used to differentiate the general-
purpose memory from the configuration registers and
should be set to 0BIN when accessing general purpose
memory. Bus address bit BA[2] can be programmed
as a “virtual 0” or biased by the A2 pin.
interaction of the various functional blocks.
A
programming Dongle (SMX3200) is available from
Summit to communicate with the SMM764. The
Dongle connects directly to the parallel port of a PC
and programs the device through a cable using the I2C
bus protocol.
Slave Address Bus Address Register Type
Write Protection Register,
Command and Status Registers,
One Configuration Registers,
ADC Conversion Readout
1001BIN
BA2 BA1 BA0
1010BIN
or
BA2 BA1 0
BA2 BA1 1
2-k Bits of General-Purpose Memory
Configuration Registers
Table 1 - Address bytes used by the SMM764.
Summit Microelectronics, Inc
2098 1.1 6/29/2005
23
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
