Chapter 9: Using User Flash Memory in MAX II Devices
9–19
Software Support for UFM Block
Figure 9–16. Full Erase Sequence Triggered Using the Slave Address
Slave Address
A A A A 111
S
A
P
R/W
6
5 4 3
'0' (write)
From Master to Slave
From Slave to Master
S – Start Condition
P – Stop Condition
A – Acknowledge
Sector Erase (Byte Address Triggered)
This sector erase operation is triggered by defining a 7- to 10-bit byte address for each
sector depending on the memory size. The trigger address for each sector is entered
on page 4 of the altufm MegaWizard Plug-In Manager, as shown in Figure 9–24 on
page 9–24. When a write operation is executed targeting this special byte address
location, the UFM sector that contains that byte address location is erased. This sector
erase operation is automatically followed by a write of the intended write byte to that
address. The default byte address location for UFM Sector 0 erase is address 0x00. The
default byte address location for UFM Sector 1 erase is [(selected memory size)/2].
You can specify another byte location as the trigger-erase addresses for each sector.
This sector erase operation supports up to eight UFM blocks or serial EEPROMs on
2
the I C bus. This sector erase operation requires acknowledge polling.
Sector Erase (A2 Triggered)
This sector erase operation uses the received A2 slave address bit to distinguish
between an erase or read/write operation. This slave operation decoding occurs when
the master transmits the slave address after generating the start condition. If the A2 bit
received by the UFM slave is 1, the sector erase operation is selected. If the A2 bit
received is 0, the read/write operation is selected. While this reserves the A2 bit as an
erase or read/write operation bit, the A0 and A1 bits still act as slave address bits to
address the UFM. With this erase option, there can be up to four UFM slaves cascaded
on the bus for 1-Kbit and 2-Kbit memory sizes. Only two UFM slaves can be cascaded
on the bus for 4-Kbit memory size, since A0 of the slave address becomes the ninth bit
(MSB) of the byte address. After the slave acknowledges the slave address and its
erase or read/write operation bit, the master can transfer any byte address within the
sector that must be erased. The internal UFM sector erase operation only begins after
the master generates a stop condition. Figure 9–17 shows the sector erase sequence
using the A2 bit of the slave address.
Figure 9–17. Sector Erase Sequence Indicated Using the A2 Bit of the Slave Address
Slave Address
S
A
Byte Address
A
P
R/W
A
= '1'
2
(1)
'0' (write)
From Master to Slave
From Slave to Master
S – Start Condition
P – Stop Condition
A – Acknowledge
Note to Figure 9–17:
(1) A2 = 0 indicates a read/write operation is executed in place of an erase. In this case, the R/W bit determines whether
it is a read or write operation.
© October 2008 Altera Corporation
MAX II Device Handbook
ALTERA [ ALTERA CORPORATION ]
