Chapter 9: Using User Flash Memory in MAX II Devices
9–5
UFM Functional Description
UFM Address Register
The MAX II UFM block is organized as a 512 × 16 memory. Since the UFM block is
organized into two separate sectors, the MSB of the address indicates the sector that
will be in action; 0 is for sector 0 (UFM0) while 1 is for sector 1 (UFM1). An ERASE
instruction erases the content of the specific sector that is indicated by the MSB of the
address register. Figure 9–2 shows the selection of the UFM sector in action using the
MSB of the address register.
Refer to “Erase” on page 9–11 for more information about ERASEmode.
Figure 9–2. Selection of the UFM Sector Using the MSB of the Address Register
Sector 0
Address Register
UFM Block
0
1
ARDin
A0
A1
A2
A3
A4
A5
A6
A7
A8
LSB
MSB
UFM Block
Sector 1
ARClk
Three control signals exist for the address register: ARSHFT, ARCLK, and ARDin.
ARSHFTis used as both a shift-enable control signal and an auto-increment signal. If
the ARSHFTsignal is high, a rising edge on ARCLKwill load address data serially from
the ARDinport and move data serially through the register. A clock edge with the
ARSHFTsignal low increments the address register by 1. This implements an auto-
increment of the address to allow data streaming. When a program, read, or an erase
sequence is executing, the address that is in the address register becomes the active
UFM location.
UFM Data Register
The UFM data register is 16 bits wide with four control signals: DRSHFT, DRCLK,
DRDin, and DRDout. DRSHFTdistinguishes between clock edges that move data
serially from DRDinor to DRDoutand clock edges that latch parallel data from the
UFM sectors. If the DRSHFTsignal is high, a clock edge moves data serially through
the registers from DRDinto DRDout. If the DRSHFTsignal is low, a clock edge
captures data from the UFM sector pointed by the address register in parallel. The
MSB is the first bit that will be seen at DRDout. The data register DRSHFTsignal will
also be used to enable the UFM for reading data. When the DRSHFTsignal is low, the
UFM latches data into the data register. Figure 9–3 shows the UFM data register.
© October 2008 Altera Corporation
MAX II Device Handbook
ALTERA [ ALTERA CORPORATION ]
