pc87591l-n05 National Semiconductor Corporation, pc87591l-n05 Datasheet - Page 80

• Manufacturer Part Number: pc87591l-n05
• Description: Lpc Mobile Embedded Controller
• Manufacturer: National Semiconductor Corporation

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4.0 Embedded Controller Modules
4.1.9
The BIU provides the following support for development systems.
Bus Status Signals
The Bus Status BST0-2 signals indicate whether a transaction on the core bus was issued; they also indicate the transaction
type; see Table 31 on page 237.
Core Bus Monitoring
The core bus monitoring cycle is a non-data transfer bus cycle. It takes a single clock cycle - T1. On this cycle:
The core bus monitoring cycle, as shown in Figure 25, is generated only when bit 1 (OBR) in BCFG register is 1.
• The address pins display the address of the internal device accessed on the core bus.
• CBRD indicates the direction of the access (read or write).
• BE0-1 indicate which data bus bytes are accessed (lower or upper).
• BST0-2 display the core bus status.
Development Support
Bus State
Figure 25. Core Bus Monitoring Bus Cycle
CLK
A0-12,
A16-20
SEL0-2,
SELIO
BE0-1
WR0-1
D0-15
CBRD
RD
BST0-2
(Continued)
T1
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