TEWS TPMC917 4MB SRAM with Battery Backup and 4 Channel RS232

Application Information

The TPMC917 is a standard single-width 32bit PMC

module providing 4MByte of SRAM with battery backup by

an on board lithium cell and four ESD protected RS232

channels (TPMC917-10R only).

The 4MByte of NV-SRAM are organized in two banks,

each providing 512K x 32bit of memory. During normal

operation (standard 5V supply applied to the SRAM) the

capacity of the lithium cell is monitored every 24 hours by

a battery monitor device and an interrupt can be

generated if the battery voltage is too low.

The monitor device switches the power supply of the

SRAM from the standard 5V to the battery if the 5V supply

drops below the battery monitor device threshold level.

Any active access to the SRAM at this point is executed

correctly within 1.5µs. After this time any further accesses

to the SRAM are not possible.

A miniature DIP switch allows the selection of the battery

backup source either from the on board lithium cell or from

an external battery via the P14 I/O connector.

The TPMC917-10R provides four RS232 channels. Each

channel has a programmable baud rate up to 115.2Kbaud.

The 4 channel UART provides a 64Byte transmit FIFO and

a 64Byte receive FIFO for each channel to significantly

reduce the overhead required to provide data to and get

data from the transmitter and the receiver. The FIFO

trigger levels are programmable. The channels are ESD

protected up to +/-15kV according to the human body

model and IEC1000-4-2.

For applications which do not need the UARTs of the

TPMC917-10R, the TPMC917-20R provides 4MByte of

NV-SRAM without any UARTs.

The TPMC917-21R has a reduced memory size. It

provides 2MByte of NV-SRAM and has no UARTs.

Software Support (TPMC917-SW-xx) for different

operating systems is available.