MEC1404 Datasheet, PDF (158/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
8.4 Interfaces
The Embedded Controller (EC) has five interfaces: ISRAM Interface, DSRAM Interface, Debug (EJTAG) Interface, AHB
System Interface, and an Interrupt Interface.
The EC executes instruction out of instruction memory (e.g., ROM) or data memory (e.g., RAM) via the ISRAM Interface;
memory accesses are handled via the DSRAM Interface; and EC accesses the peripherals residing in the internal
address space via the AHB interface. The host can probe the EC and all EC addressable memory via the eJTAG debug
interface.
FIGURE 8-1:
MIPS32 M14K EMBEDDED CONTROLLER I/O BLOCK DIAGRAM
Decode
M14K Core Wrapper
M14K Core
microMIPS
ISRAM
Interface
ISRAM
I/F
System
Interface
Execution Unit
ALU/Shift
Atomic/LdSt
System
Coprocessor
GPR
(no shadow sets)
MDU
(Performance Opt)
Debug
Break Points
MMU
SRAM
Controller
DSRAM
Interface
Power Mgt
Interrupt
Interface
Interrupt
Aggregator
eJTAG
Interface
ICSP
Processor‐to‐
Memory
Translator
Memory
Controller
DSRAM
I/F
AHB I/F
EC Address Space
2‐wire
debug
Note:
8.4.1
Blocks in the diagram that are external to the M14K Core and are highlighted in blue are defined in their
respective chapters.
EJTAG INTERFACE
TABLE 8-1: EJTAG SIGNAL DESCRIPTION TABLE
Signal Name
TCK
TMS
TDI
TDO
TRST#
Pin Name
JTAG_CLK
JTAG_TMS
JTAG_TDI
JTAG_TDO
JTAG_RST#
Direction
Input
Input
Input
Output
Input
Description
Test Clock
Test Mode Select
Test Data In
Test Data Out
Test Reset, low active
DS00001956D-page 158
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