C8051F326-TB Silicon Laboratories Inc, C8051F326-TB Datasheet - Page 69

• Manufacturer Part Number: C8051F326-TB
• Description: BOARD PROTOTYPING W/C8051F326
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F326-TB

• Contents: Board
• Processor To Be Evaluated: C8051F326/F327
• Interface Type: USB
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051F326
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

9.
The C8051F326/7 devices include 1280 bytes of on-chip XRAM. This XRAM space is split into user RAM
(addresses 0x0000–0x03FF) and USB0 FIFO space. The USB0 FIFO space is only accessible through the
USB FIFO registers.
9.1.
User XRAM can 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 Con-
trol Register (EMI0CN as shown in Figure 9.1). Note: the MOVX instruction is also used for writes to the
Flash memory. See Section “8. Flash Memory” on page 63 for details. The MOVX instruction accesses
XRAM by default.
For any of the addressing modes, the upper 6 bits of the 16-bit external data memory address word are
"don't cares". As a result, the 1024-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 0x0400,
0x0800, 0x0C00, 0x1000, etc.
External RAM
Accessing User XRAM
0 x F F F F
0 x0 3 F F
0 x0 4 0 0
0 x0 0 0 0
Figure 9.1. External Ram Memory Map
0 x0 0 0 0 to 0 x 0 3 F F , w ra p p e d
S a m e 1 0 2 4 b y te s a s fro m
o n 1 K -b y te b o u n d a rie s
1 0 2 4 B y te s
X R A M
Rev. 1.1
A c ce ss e d o n ly th ro u g h U S B
F IF O re g iste rs (in a c ce ss ib le
u s in g th e M O V X in s tru ctio n)
A cc e s s e d w ith th e M O V X
in stru c tio n
U S B F IF O s
2 5 6 B y te s
C8051F326/7
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