MTC20136 ST Microelectronics, Inc., MTC20136 Datasheet - Page 13

• Manufacturer Part Number: MTC20136
• Description: Adsl Transceiver Controller
• Manufacturer: ST Microelectronics, Inc.

Table 1. (continued)
Memory map modes
Three modes are defined :
a) Normal mode:
The internal RAM is mapped in the lower part of memory. This is the normal operating mode, it allows
maximum speed access to exception vectors.
b) Normal boot mode:
If the TROM external pin is high at reset, the MTC20136 boots from an external FEPROM.
c) Internal boot mode:
If the TROM external pin is low at reset, the MTC20136 boots from its internal ROM. This mode can be
used to perform code download from a host.
Boot modes are used at RESET time.
Boot_M0 andBoot_M1 on pin 26 and 27 conrol the port to be used for downloading the code into the
SDRAM after Bootup. This when TROM is low.
MTC20135, MTC20455 access
The MTC20136 directly connects to the MTC20135 without glue logic. Following features are provided for
MTC20135 access :
– 16 bit multiplexed address/data bus giving 64Kbyte address space per MTC20135.
– synchronous ready-controlled operation - control signals : nCS[4:7], E_CLK, ALE, W/nR, nRDYRCV
– Little endian byte ordering on 16 bit bus - nRDYRCV timeout mechanism
The timing diagram of the access to the MTC20135 or MTC20455 is shown in figure 3:
E_nRDYRCV
E_nCS [1:0]
E_nCS [7:4]
E_A [15:0]
E_D [15:0]
Pin Name
E_nCS_S
E_nWE0
E_nWE1
E_nOE
E_ALE
E_Clk
Boot_M1
(Pin27)
0
1
1
MTC20135, MTC20455
access function
nRDYRCV
AD [15:0]
nCS [7:4]
W/nR
E-Clk
ALE
-
-
-
-
-
Boot_M0
(Pin26)
1
0
1
9600 Bps via serail port 1
Par. CTRL-E
Par.CTRL-E
access function
S_Q [15:0]
S_A [11:0]
SDRAM
S_nWE
S_nCS
S_Clk
-
-
-
-
-
-
access function
SRAM/FEPROM
E_nCS [1:0]
E_A [15:0]
E_D [15:0]
E_nWE0
E_nWE1
E_nOE
-
-
-
-
-
MTC20136
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