C8051F005DK Silicon Laboratories Inc, C8051F005DK Datasheet - Page 92

• Manufacturer Part Number: C8051F005DK
• Description: DEV KIT FOR F005/006/007
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F005DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F01x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F005
• Silicon Family Name: C8051F00x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Silicon Laboratories C8051 F005/006/007
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1188

12. EXTERNAL RAM (C8051F005/06/07/15/16/17)
The C8051F005/06/07/15/16/17 MCUs include 2048 bytes of RAM mapped into the external data memory space.
All of these address locations may be accessed using the external move instruction (MOVX) and the data pointer
(DPTR), or using MOVX indirect addressing mode. If the MOVX instruction is used with an 8-bit address operand
(such as @R1), then the high byte of the 16-bit address is provided by the External Memory Interface Control
Register (EMI0CN as shown in Figure 12.1). Note: the MOVX instruction is also used for writes to the Flash
memory. See Section 11 for details. The MOVX instruction accesses XRAM by default (i.e. PSTCL.0 = 0).
For any of the addressing modes the upper 5-bits of the 16-bit external data memory address word are “don’t cares”.
As a result, the 2048-byte RAM is mapped modulo style over the entire 64k external data memory address range.
For example, the XRAM byte at address 0x0000 is also at address 0x0800, 0x1000, 0x1800, 0x2000, etc. This is a
useful feature when doing a linear memory fill, as the address pointer doesn’t have to be reset when reaching the
RAM block boundary.
Bits 7-3: Not Used – reads 00000b
Bits 2-0: PGSEL[2:0]: XRAM Page Select Bits
Bit7
R
-
The XRAM Page Select Bits provide the high byte of the 16-bit external data memory
address when using an 8-bit MOVX command, effectively selecting a 256-byte page of
RAM. The upper 5-bits are “don’t cares”, so the 2k address blocks are repeated modulo
over the entire 64k external data memory address space.
000: xxxxx000b
001: xxxxx001b
010: xxxxx010b
011: xxxxx011b
100: xxxxx100b
101: xxxxx101b
110: xxxxx110b
111: xxxxx111b
Bit6
Figure 12.1. EMI0CN: External Memory Interface Control
R
-
Bit5
R
-
Bit4
R
-
Rev. 1.7
Bit3
R
-
PGSEL2
R/W
Bit2
C8051F000/1/2/5/6/7
C8051F010/1/2/5/6/7
PGSEL1
R/W
Bit1
PGSEL0
R/W
Bit0
SFR Address:
Reset Value
00000000
0xAF
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