Host Programmer Model
Host Interface (HI08)
6
-29
6.7.4
Interrupt Vector Register (IVR)
The IVR is an 8-bit read/write register that typically contains the interrupt vector number used
with MC68000 family processor vectored interrupts. Only the host processor can read and
write this register. The contents of the IVR are placed on the host data bus, H[7–0], when both
the
HREQ
and
HACK
signals are asserted. The contents of this register are initialized to $0F by
a hardware or software reset. This value corresponds to the uninitialized interrupt vector in
the MC68000 family.
1
TXDE
1
Transmit Data Register Empty
Indicates that the transmit byte registers (TXH:TXM:TXL) are empty and
can be written by the host processor. TXDE is set when the contents of
the transmit byte registers are transferred to the HRX register. TXDE is
cleared when the transmit register (TXL or TXH according to HLEND bit)
is written by the host processor. The host processor can set TXDE using
the initialize function. TXDE can assert the external HTRQ signal if the
TREQ bit is set. Regardless of whether the TXDE interrupt is enabled,
TXDE indicates whether the TX registers are full and data can be latched
in (so that polling techniques may be used by the host processor).
Hardware, software, individual, and stop resets all set TXDE.
0
RXDF
0
Receive Data Register Full
Indicates that the receive byte registers (RXH:RXM:RXL) contain data
from the DSP56303 to be read by the host processor. RXDF is set when
the HTX is transferred to the receive byte registers. RXDF is cleared when
the host processor reads the receive data register (RXL or RXH according
to HLEND bit). The host processor can clear RXDF using the initialize
function. RXDF can assert the external HREQ signal if the RREQ bit is
set. Regardless of whether the RXDF interrupt is enabled, RXDF indicates
whether the RX registers are full and data can be latched out (so that the
host processor can use polling techniques).
7
6
5
4
3
2
1
0
IV7
IV6
IV5
IV4
IV3
IV2
IV1
IV0
Figure 6-18. Interrupt Vector Register (IVR)
Table 6-17. Interface Status Register (ISR) Bit Definitions (Continued)
Bit Number
Bit Name
Reset Value
Description
Summary of Contents for DSP56303
Page 1: ...DSP56303 User s Manual 24 Bit Digital Signal Processor DSP56303UM AD Revision 1 January 2001 ...
Page 52: ...JTAG OnCE Interface 2 22 DSP56303 User s Manual ...
Page 114: ...General Purpose Input Output GPIO 5 10 DSP56303 User s Manual ...
Page 212: ...GPIO Signals and Registers 8 26 DSP56303 User s Manual ...
Page 268: ...Interrupt Equates A 22 DSP56303 User s Manual ...
Page 306: ...Programming Sheets B 38 DSP56303 User s Manual ...
Page 320: ...Index 14 DSP56303 User s Manual ...