
Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
21-30
Freescale Semiconductor
External Memory Controller (EMC)
21.3.2.10 Transfer Error Status Register (TESR)
The EMC has five registers for error management:
•
TESR indicates the cause of an error.
•
TEDR enables/disables error checking.
•
TEIR enables/disables reporting of errors through an interrupt.
•
TEATR captures the source attributes of an error.
•
TEAR captures the address of a transaction that caused an error.
TESR is a write-clear type of register. Reading from the TESR register occurs normally; however, write
operations can clear but not set bits. A bit is cleared whenever the register is written and the data in the
corresponding bit location is a 1. For example, to clear the write protect error bit (TESR[WP]) and not
affect any other bits in the register, the value 0x00_0400 should be written to the register.
NOTE
The TESR register has no low part. The low part is reserved and the
corresponding address should not be used.
Table 21-41. SDRAM Refresh Timer
SRT
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
X:0xFF_FE53
R
SRT
W
R
SRT
W
Reset
0x00_0000
Table 21-42. SRT Field Descriptions
Bits
Name
Description
23–16
—
Reserved
15–8
SRT
SDRAM refresh timer period. Determines, along with the timer prescaler (MRTPR), the timer period
according to the following equation:
Note that a value of 0x00 (reset value) sets the maximum period of 256 x MRTPR[PTP] system clock
cycles.
Example: For a 200 MHz system clock and a required refresh rate of 16 µs, and given
MRTPR[PTP] = 32, the SRT value should be 100 (decimal). 100/(200 MHz/32) = 16 µs, which meets the
demand for required refresh period of 16 µs.
7-0
—
Reserved
TimerPeriod
SRT
Fsystemclock
MRTPR PTP
[
]
----------------------------------------
⎝
⎠
⎛
⎞
----------------------------------------------
=