7–24
Chapter 7: User Flash Memory in MAX V Devices
Software Support for UFM Block
The Quartus II software supports both the Base mode (uses 8-bit address and data)
and the Extended mode (uses 16-bit address and data). Base mode uses only UFM
sector 0 (2,048 bits), while Extended mode uses both UFM sector 0 and sector 1 (8,192
bits). There are only four pins in SPI: SI
,
SO
,
SCK, and nCS. Table 7–9 describes the SPI
pins and functions.
Table 7–9. SPI Interface Signals
Pin
Description
Serial Data Input
Function
SI
SO
Receive data serially.
Transmit data serially.
Serial Data Output
The clock signal produced from the master device to
synchronize the data transfer.
SCK
nCS
Serial Data Clock
Active low signal that enables the slave device to
receive or transfer data from the master device.
Chip Select
Data transmitted to the SIport of the slave device is sampled by the slave device at
the positive SCKclock. Data transmits from the slave device through SOat the negative
SCK clock edge. When nCSis asserted, it means the current device is being selected by
the master device from the other end of the SPI bus for service. When nCSis not
asserted, the SIand SCKports should be blocked from receiving signals from the
master device, and SOshould be in High Impedance state to avoid causing contention
on the shared SPI bus. All instructions, addresses, and data are transferred with the
MSB first and start with high-to-low nCStransition. The circuit diagram is shown in
Figure 7–20.
Figure 7–20. Circuit Diagram for SPI Interface Read or Write Operations
SI SO SCK nCS
Op-Code Decoder
Read, Write, and Erase
State Machine
SPI Interface
Control Logic
UFM Block
Address and Data Hub
Eight-Bit Status Shift Register
MAX V Device Handbook
January 2011 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
