PC87383 datasheet(20/77 Pages) NSC

20 / 77 page

3.0 Device Architecture and Configuration (Continued)

www.national.com

Revision 1.1

3.2.2

Banked Logical Device Registers Structure

Each functional block is associated with a Logical Device Number (LDN). The configuration registers are grouped into banks,

where each bank holds the standard configuration registers of the corresponding logical device. Table 8 shows the LDN val-

ues of the PC87383 functional blocks. Any value not listed is reserved.

Figure 4 shows the structure of the standard configuration register file. The LDN and PC87383 configuration registers are

not banked and are accessed by the Index-Data register pair only, as described in Section 3.2.1. However, the device control

and device configuration registers are duplicated over four banks for four logical devices. Therefore, accessing a specific

register in a specific bank is performed by two-dimensional indexing, where the LDN register selects the bank (or logical

device) and the Index register selects the register within the bank. Accessing the Data register while the Index register holds

a value of 30h or higher physically accesses the logical device configuration registers currently pointed to by the Index reg-

ister, within the logical device currently selected by the LDN register.

Figure 4. Structure of Standard Conﬁguration Register File

Table 8. Logical Device Number (LDN) Assignments

Write accesses to unimplemented registers (i.e. accessing the Data register while the Index register points to a non-existing

04h (indicating no DMA channel is active). The configuration registers are accessible immediately after reset.

LDN

Functional Block

01h

Parallel Port (PP)

02h

Infrared (IR)

03h

Serial Port 1 (SP1)

07h

General-Purpose I/O (GPIO) Ports

07h

20h

30h

60h

75h

FFh

Logical Device Number Register

SuperI/O Configuration Registers

Logical Device Control Register

Standard Logical Device

Special (Vendor-defined)

Configuration Registers

Banks

2Fh

F0h

Bank Select

63h

74h

70h

71h

Configuration Registers

(One per logical device)

Logical Device

PC87383 Datasheet(PDF) 20 Page - National Semiconductor (TI)

PC87383 Datasheet(HTML) 20 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77

Datasheet Download

Link URL